Suture delivery device

ABSTRACT

A device is configured for closing an aperture in a wall of a blood vessel. An embodiment of the device includes a body and at least one suture element held within the body. A suture capture rod is positioned within the body and is operatively associated with the suture element and arranged to pass the suture element through a vessel wall such that opposed portions of the suture element extend from the vessel wall. A removable guidewire segment is removably attached to a distal end of the body.

REFERENCE TO PRIORITY DOCUMENT

This application is a continuation of U.S. patent application Ser. No.13/961,745 (now issued as U.S. Pat. No. 10,159,479), filed Aug. 7, 2013,which claims priority of U.S. Provisional Patent Application Ser. No.61/681,584, filed on Aug. 9, 2012, and entitled “Suture DeliveryDevice,” the disclosures of which are hereby incorporated by referencein their entirety.

BACKGROUND

The present disclosure relates generally to medical methods and devices.More particularly, the present disclosure relates to methods and devicesfor suture “pre-closing” a vessel, in other words, deploying closuresutures for puncture wounds into blood vessels wherein the sutures areapplied before the vessel is accessed with a sheath or cannula.

Medical procedures for gaining intravascular arterial access arewell-established, and fall into two broad categories: surgical cut-downand percutaneous access. In a surgical cut-down, a skin incision is madeand tissue is dissected away to the level of the target artery.Depending on the size of the artery and of the access device, anincision is made into the vessel with a blade, or the vessel ispunctured directly by the access device. In some instances, amicro-puncture technique is used whereby the vessel is initiallyaccessed by a small gauge needle, and successively dilated up to thesize of the access device. For percutaneous access, a puncture is madefrom the skin, through the subcutaneous tissue layers to the vessel, andinto the vessel itself. Again, depending on the size of the artery andof the access device, the procedure will vary, for example a Seldingertechnique, modified Seldinger technique, or micro-puncture technique isused.

Because arteries are high-pressure vessels, additional maneuvers may berequired to achieve hemostasis after removal of the access device fromthe vessel. In the case of surgical cut-down, a suture may be used toclose the arteriotomy. For percutaneous procedures, either manualcompression or a closure device may be used. While manual compressionremains the gold standard with high reliability and low cost, closuredevices require less physician time and lower patient recovery time. Inaddition, closure devices are often required for procedures with largeraccess devices and/or for patients with anti-coagulation andanti-platelet therapy. Examples of closure devices include suture-basedclosure devices such as the Abbott Vascular PERCLOSE or ProStar familyof devices or the Sutura SUPERSTITCH device. Other closure devicesinclude clip closure devices such as the Abbott Vascular STARCLOSEdevice, or “plug” closure devices such as the Kensey Nash/St. JudeMedical ANGIOSEAL device.

In certain types of procedures, it is advantageous to “pre-close” thearteriotomy, for example if the arteriotomy is significant in size, ifthe arteriotomy site is difficult to access, or if there is a heightenedrisk of inadvertent sheath removal. The term “suture pre-close” refersto deploying closure sutures for puncture wounds into blood vesselswherein the sutures are applied before the vessel is accessed with theprocedural sheath or cannula. The ability to gain rapid hemostaticcontrol of the access site can be critical. In an open surgicalprocedure, a suture is sometimes placed into the vessel wall in aU-stitch, Z-stitch, or purse-string pattern prior to vessel access. Thearteriotomy is made through the center of this stitch pattern. Thesuture may be tensioned around the sheath during the procedure, or thesuture may be left loose. Generally, the two ends of the suture exit theincision and are anchored during the procedure, for example withhemostatic forceps. If the sheath is inadvertently removed from thearteriotomy, rapid hemostasis may be achieved by applying tension to theends of the suture. After removal of the sheath from the arteriotomy,the suture is then tied off to achieve permanent hemostasis.

In percutaneous procedures, it is not possible to insert a closingsuture in the manner described above. In these procedures, if suturepre-close is desired, a percutaneous suture-based vessel closure devicewould need to be used. However, current percutaneous suture-based vesselclosure devices require previous dilatation (widening) of the initialneedle puncture to be inserted into the vessel, and are designed to beplaced after the procedural sheath has been inserted into, and in somecases removed from the arteriotomy. In this manner, the dilatation hasbeen accomplished by the procedural sheath and dilator itself. In viewof this, current suture-based vessel closure devices have certainlimitations for use in pre-closure of an arteriotomy. To accomplishpre-closure with these devices, a dilator or dilator/sheath combinationneeds to be initially inserted into the vessel over a guidewire todilate the arteriotomy puncture, and then exchanged for the closuredevice, with the difficulty of maintaining hemostasis during thisexchange.

Another limitation is that once the suture is placed in the vessel withthe suture-based vessel closure devices, it is likewise difficult tomaintain hemostasis during removal of the suture-based vessel closuredevice and insertion of the procedural sheath. Similarly, once theprocedural sheath is removed, it is difficult to maintain hemostasisbefore the final suture knot is tied. Or, if the suture is pre tied, itis difficult to maintain hemostasis before knot is pushed into place. Inaddition, current suture-based vessel closure devices do not have anymeans to gain rapid access to the suture ends to apply tension in theinstance of inadvertent sheath removal.

Certain procedures, for example intervention of the carotid arteries,offer additional clinical challenges. In a transcervical approach totreatment of the internal carotid artery and/or the carotid arterybifurcation, the distance from the access site to the treatment site isusually less than 5-7 cm. Therefore it is desirable to limit the lengthof the pre-closure device or any associated accessories (needlepuncture, guidewire, micro introducer, dilator, or sheath itself) to 3-4cm, to remove risk of incursion into the plaque zone and reduce the riskof generating embolic particles. In the case of the Abbott ProStar orPerclose, the vessel entry device requires about a 15 cm length into thevessel. With other devices, there are no methods or features forlimiting or controlling the amount of egress of these device componentsin the vessel. In addition, the consequences of failure of the closuredevices to achieve complete hemostasis are great. If the suture closuredid not achieve full hemostasis, the resultant hematoma may lead to lossof airway passage and/or critical loss of blood to the brain, both ofwhich lead to severe patient compromise and possibly death.

SUMMARY

Disclosed is a suture-based blood vessel closure device that can performthe dilation of an arteriotomy puncture, and therefore does not requireprevious dilation of the arteriotomy puncture by a separate device or bya procedural sheath dilator. The suture-based vessel closure device canplace one or more sutures across a vessel access site such that, whenthe suture ends are tied off after sheath removal, the stitch orstitches provide hemostasis to the access site. The sutures can beapplied either prior to insertion of a procedural sheath through thearteriotomy or after removal of the sheath from the arteriotomy. Thedevice can maintain temporary hemostasis of the arteriotomy afterplacement of sutures but before and during placement of a proceduralsheath and can also maintain temporary hemostasis after withdrawal ofthe procedural sheath but before tying off the suture. A suture-basedvessel closure device also desirably can provide rapid access andcontrol of suture ends in the instance of inadvertent sheath removal aswell as provide a highly reliable hemostatic closure of the access site.

In one aspect, there is disclosed a device for closing an aperture in awall of a blood vessel, the device comprising: a body; at least onesuture element held within the body; at least one suture capture rodwithin the body, the suture capture rod being operatively associatedwith the suture element and arranged to pass the suture element throughthe vessel wall such that opposed portions of the suture element extendfrom the vessel wall; and a removable guidewire segment removablyattached to a distal end of the body

In another aspect, there is disclosed a method of delivering a suture toan arterial access site, comprising: inserting a removable distalguidewire segment of a suture applier device into an artery such that adistal region of the guidewire segment is in the artery and a proximalregion of the guidewire segment is outside the artery; attaching theproximal region of the guidewire segment to a distal end of a suturedelivery device; deploying a suture into a wall of the artery using thesuture delivery device while the guidewire segment is attached to thedistal end of the suture delivery device; removing the suture deliverydevice so that the distal end of the suture delivery device is outsidethe body but the distal end of the guidewire segment remains in theartery; detaching the suture delivery device from the guidewire segmentso that the proximal region of the guidewire segment is detached andoutside the body; and attaching a guidewire extension to the proximalend of the guidewire segment such that the guidewire segment andguidewire extension collectively form an extended guidewire having aregion inside the artery and a region outside the artery.

Other features and advantages should be apparent from the followingdescription of various embodiments, which illustrate, by way of example,the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-1C show a suture-based vessel closure device or suture deliverydevice that can be used to position a loop of suture across a puncturein a blood vessel.

FIG. 2 shows a close-up view of a distal region of the closure devicewith the vessel wall locator in the deployed position.

FIGS. 3A and 3B show cross-sectional views of the delivery shaft of theclosure device along line 3A-3A of FIG. 2.

FIGS. 4A and 4B show a close-up view of an alternate embodiment of thedistal portion of a suture delivery device that can be used to positiona loop of suture across a puncture in a blood vessel.

FIGS. 5 and 6 show two embodiments of a pre-mounted sheath beingadvanced along the closure device after the suture has been placedacross the arteriotomy.

FIGS. 7A-7B show another embodiment of a suture-based vessel closuredevice or suture delivery device.

FIGS. 8 and 9 show portions of another embodiment of a suture deliverydevice.

FIG. 10A is a perspective view of an embodiment of a distal region of asuture delivery device with the suture clasp arms partially deployed.

FIG. 10B is a perspective view of the suture delivery device with thesuture clasp arms fully deployed.

FIG. 10C shows two flexible needles extending out of needle aperturesand engaging the suture clasp arms.

FIGS. 11A-13 show a guidewire with deployment of an expandable sealingelement or elements to be used with a closure device

FIG. 14 shows a guidewire embodiment having an intravascular anchor.

FIGS. 15-17 shows another guidewire anchor embodiment wherein theguidewire attaches to one or more clips that can be secured to the skinof the patient to hold the guidewire in place.

FIGS. 18A-18C show an embodiment of the closure device wherein aself-closing material is pre-loaded on a proximal region of the deliveryshaft.

FIGS. 19A-19C show an embodiment wherein a hemostasis material ispositioned over the arteriotomy location after removal of a proceduralsheath.

FIG. 20 shows a first embodiment of a retrograde flow system that isadapted to establish and facilitate retrograde or reverse flow bloodcirculation.

FIG. 21A illustrates an arterial access device useful in the methods andsystems of the present disclosure.

FIG. 21B illustrates an additional arterial access device constructionwith a reduced diameter distal end.

FIGS. 22A and 22B illustrate a tube useful with the sheath of FIG. 20A.

FIG. 23A illustrates an additional arterial access device constructionwith an expandable occlusion element.

FIG. 23B illustrates an additional arterial access device constructionwith an expandable occlusion element and a reduced diameter distal end.

FIGS. 24 and 25 show an embodiment wherein a proximal extension isremovably connected to the Y-arm connector at a connection site.

FIG. 26 illustrates a first embodiment of a venous return device usefulin the methods and systems of the present disclosure.

FIG. 27 illustrates an alternative venous return device useful in themethods and systems of the present disclosure.

FIG. 28 illustrates the system of FIG. 20 including a flow controlassembly.

FIGS. 29A-29D, FIGS. 30A-30D, FIGS. 31A and 31B, FIGS. 32A-32D, andFIGS. 33A and 33B, illustrate different embodiments of a variable flowresistance component useful in the methods and systems of the presentdisclosure.

FIGS. 34A-34B, FIGS. 35A-35B, FIGS. 36A-36D, and FIGS. 37A-37Billustrate further embodiments of a variable flow resistance systemuseful in the methods and systems of the present disclosure.

FIGS. 38A-38E, 39, 40A-40E, and 41A-41F show operations in an exemplaryinterventional procedure.

FIGS. 42A-42B show an additional embodiment of a suture delivery device.

FIGS. 43-47 show an exemplary method of use of the device of FIGS.42A-42B.

DETAILED DESCRIPTION

Disclosed is a suture-based blood vessel closure device that can performthe dilation of an arteriotomy puncture, and therefore does not requireprevious dilation of the arteriotomy puncture by a separate device or bya procedural sheath dilator. The suture-based vessel closure device canplace one or more sutures across a vessel access site such that, whenthe suture ends are tied off after sheath removal, the stitch orstitches provide hemostasis to the access site. The sutures can beapplied either prior to insertion of a procedural sheath through thearteriotomy or after removal of the sheath from the arteriotomy. Thedevice can maintain temporary hemostasis of the arteriotomy afterplacement of sutures but before and during placement of a proceduralsheath and can also maintain temporary hemostasis after withdrawal ofthe procedural sheath but before tying off the suture. A suture-basedvessel closure device also desirably can provide rapid access andcontrol of suture ends in the instance of inadvertent sheath removal aswell as provide a highly reliable hemostatic closure of the access site.

FIG. 1A shows a suture-based vessel closure device or suture deliverydevice 5 that can be used to position a loop of suture across a puncturein a blood vessel. The suture delivery device 5 generally includes abody comprised of a delivery shaft 7 attached to a proximal housing 9having control elements such as a movable actuation handle 11 and/oractuation lever 13. The type, number, and shape of the control elementscan vary. In an embodiment, the actuation handle 11 controls movement ofa pair of suture capture rods 15 (shown in FIG. 1C). The actuation lever13 controls positioning of a vessel wall locator 17 (shown in FIGS. 1Band 1C). At least one of the suture capture rods 15 is coupled to asuture 19 (FIG. 2) in a manner that permits a loop of the suture to bepositioned across an arteriotomy for closure of the arteriotomy. Thedelivery device 5 may be at least partially configured in the mannerdescribed in U.S. Pat. No. 7,001,400, which is incorporated herein byreference in its entirety. As used herein, the term “proximal” meanscloser to the user and the term “distal” means further from the user.

With reference still to FIG. 1A, the device 5 includes a distal tip 21that extends distally of a distal end of the delivery shaft 7. Asdescribed in detail below, in an embodiment the distal tip 21 is adaptedto dilate an arteriotomy. A guidewire lumen extends entirely through thesuture delivery device 5 from the distal end of the distal tip 21 to aproximal exit port of the delivery device 5. The guidewire lumen permitsthe entire delivery device 5 to be placed over a guidewire, for example,a 0.035 or a 0.038 inch guidewire. The axis of the delivery shaft 7 neednot be straight, as the shaft may curve somewhat.

With reference to FIG. 1B, a vessel wall locator 17 in the form of afoot is movably positioned near the distal end of the delivery shaft 7.The vessel wall locator 17 moves between a stored position, in which thevessel wall locator 17 is substantially aligned along an axis of thedelivery shaft 7 (as shown in FIG. 1A), and a deployed position, inwhich the vessel wall locator 17 extends laterally from the deliveryshaft 7 (as shown in FIGS. 1B and 1C). In the stored position, thevessel wall locator 17 can be disposed within a receptacle of thedelivery shaft 7 so as to minimize the cross-section of the deviceadjacent the vessel wall locator 17 prior to deployment.

The vessel wall locator 17 is coupled via a control element such as acontrol wire to the actuation element 13 on the handle 9. As shown inFIGS. 1A-1C, movement of the actuation element 13 causes movement of thevessel wall locator 17 between the stored position and deployedposition. Actuation of the actuation element 13 slides the control wire(contained within the delivery shaft 7) proximally, pulling the vesselwall locator 17 from the stored position to the deployed position.

Suture capture rods 15 (FIG. 1C) are coupled to the actuation handle 11.Actuation of the actuation handle 11 cause the capture rods 15 to movebetween a non-deployed position wherein the capture rods 15 arecontained in the delivery shaft 7 (shown in FIGS. 1A and 1B), and adeployed position (shown in FIG. 1C) wherein the capture rods advancedistally outward of the delivery shaft 7 toward the vessel wall locator17. In the deployed position, distal ends of the capture rods 15 matewith suture capture collars contained in lateral ends of the vessel walllocator 17.

Movement of the suture capture rods 15 to the deployed position causesat least one end of the suture to couple to the suture capture rods 15.The suture capture rods 15 can then be used to proximally draw the endsof the sutures through the vessel wall for forming a suture loop aroundthe arteriotomy. At the end of the procedure after a procedural sheathhas been removed, the suture can be tied in a knot and tighteneddistally against the arteriotomy to seal the arteriotomy. This can beachieved in various manners, some of which are described in U.S. Pat.No. 7,001,400, which is incorporated by reference in its entirety. In anembodiment, a short length of flexible filament 29 (FIG. 2) extendssubstantially directly between suture capture elements in the vesselwall locator 17. One suture capture rod attaches a suture 19 to one endof flexible filament. In this manner, the flexible filament links thesuture 19 to the opposing suture capture rod. As the rods are drawn backusing actuator 11, the flexible filament pulls the suture 19 through thevessel wall on one side of the arteriotomy, across the arteriotomy, andout the other side. When the actuator 11 has fully pulled out the suturerods 15, both ends of the suture 19 can be retrieved.

FIG. 2 shows a close-up view of a distal region of the delivery device 5with the vessel wall locator 17 in the deployed position. The deliverydevice 5 is shown in partial cross-section to illustrate the internalcomponents. The distal tip 21 tapers smoothly to the diameter of thedelivery shaft 7 to permit the distal tip 21 to be used as a dilator. Asmentioned, the tapered distal tip 21 dilates the arteriotomy as thedelivery device 5 enters the blood vessel. In this regard, the distaltip 21 has features that are particularly adapted for dilating anarteriotomy. Such features include size, shape, materials, and/ormaterial properties that are specifically adapted to dilate anarteriotomy. For example, the dilating distal tip 21 is constructed frommaterials and dimensions to reproduce the dilating function of astandard sheath dilator. For example, at least a portion of the tip mayhave a taper angle of 3° to 7° relative to a longitudinal midline axisof the suture closure device. In an embodiment, the distal tip has anequivalent stiffness and smoothness to polyethylene material. In anembodiment, the tapered portion of the tip 21 extends over a length ofabout 1 to 3 cm or about 1 to 2 cm. The tapered portion may taperoutward from the distal-most location of the distal tip 21. It should beappreciated that the distal tip 21 is not required to be a dilating tip.

In addition, the distal tip 21 includes a guidewire lumen 31. As shownin FIG. 2, the guidewire lumen may extend through the entire device, oralternately through the entire distal region and delivery shaft 7 andexit distal to the proximal handle 9. In yet another alternateembodiment, the guidewire lumen extends through the dilator tip to apoint on one side of the distal region of the suture delivery devicedistal to the vessel wall locator. In this latter case, the guidewirerides only over the distal region of the suture delivery device, ratherthan through the delivery shaft.

The guidewire lumen 31 forms an opening or exit at the distal end of thedistal tip 21. The distal exit of the guidewire lumen 31 provides asmooth transition to the guidewire, so the device can smoothly andatraumatically be inserted into the vessel over the guidewire. Thus thediameter of the guidewire lumen may be close to the diameter of theguidewire itself when it exits the dilating tip. For example, forcompatibility with an 0.035″ or 0.038″ guidewire, the dilating tip ofthe device can have a guidewire lumen of from 0.039″ to 0.041″ as itexits the tip (although it could be slightly larger for the remainder ofthe device). In addition, the leading edge of the dilating tip may beradiused, for example 0.050″ to 0.075″ radius, so there are no abrupttransitions as the device enters the vessel. Thus, as mentioned, aseparate dilator is not needed to dilate the arteriotomy beforedeployment of the delivery device 5 through the arteriotomy. In anembodiment, the distal tip is located about 3 cm beyond the stitchdelivery location, thus, about 3 cm distal of the vessel wall locator17.

The distal portion of the delivery shaft 7 may include a positionverification lumen that extends proximally from a position verificationport just proximal to the vessel wall locator 17 to a position indicatorat the housing 9. When the vessel wall locator 17 is properly positionedwithin the blood vessel, blood pressure causes blood to flow proximallyinto the position verification port, through the position verificationlumen, and to the position indicator in the housing 9. Presence of bloodin the position indicator provides an indication that the vessel walllocator 17 has entered the blood vessel and may be actuated to the“open” position (as in FIG. 1B). The position indicator may comprise ablood exit port, a clear receptacle in which blood is visible, or thelike. It should be understood that a wide variety of alternativeposition verifications sensors might be used, including electricalpressure sensors, electrolytic fluid detectors, or the like.

With reference still to FIG. 2, a guidewire 33 slidably extends throughthe guidewire lumen 31 via an opening in the center of the distal tip 21of the device 5. At a distal-most location, the guidewire lumen 31 iscentered in the distal tip 21. That is, the guidewire 31 is aligned withthe longitudinal midline or center-axis of the distal tip 21. Theguidewire lumen 31 transitions toward an off-center position movingproximally through the delivery shaft 7. That is, at a location proximalof the distal most location of the distal tip 21, the guidewire lumentransitions to a position that is offset from the longitudinalcenter-axis of the delivery shaft 7. The vessel wall locator 17 ispositioned on the delivery shaft 7 such that the suture placement siteis centered around the delivery shaft 7. Thus, the sutures are placed atthe center of the vessel puncture even though the guidewire 33 isoff-center in the delivery shaft 7. Alternately, the guidewire lumen maybe positioned in the central axis of the delivery shaft, and the vesselwall locator and suture placement sites are centered offset from theshaft central axis.

FIGS. 3A and 3B show a cross-sectional view of the delivery shaft 7along line 3A-3A of FIG. 2. A pair of channels 35 extend longitudinallythrough the delivery shaft 7 near the outer surface of the deliveryshaft. Each of the channels 35 communicates with a slot 37 that providesexternal access to the respective channel 35. In FIG. 3A, a suturecapture rod 15 is positioned within each of the channels 35. The slot issized and shaped such that the suture capture rod 15 is securelycontained within the channel 35. In FIG. 3B, the suture capture rodshave been pulled proximally, pulling the suture 19 with them; thus thefigure shows the suture 19 positioned within each of the channels 35. Asshown in FIG. 3B, the slots are larger than the suture 19 such that thesuture 19 can be removed through the slots 37, such as by being peeledout of the slots 37.

FIGS. 4A and 4B show a close-up view of an alternate embodiment of thedistal portion of a suture delivery device 5 that can be used toposition a loop of suture across a puncture in a blood vessel. A similardevice is described in U.S. Pat. No. 7,004,952, which is incorporated byreference in its entirety. FIGS. 4A and 4B show the device 5 with a bodycomprised of the shaft 7 truncated in order to illustrate features ofthe device 5. The vessel wall locator is in the form of two extendablearms 39. As with the previous embodiment, the vessel wall locator may becoupled via a rod or other coupler to an actuation element 13 on ahandle 9. A loop of suture 19 is positioned down the center of thedelivery shaft 7 such that both ends of the suture 19 exit out a distalport 23 of the delivery shaft 7. The middle 25 of the loop of suture 19exits out the proximal end of the delivery device 5. Each end of thesuture loop is attached to the end of each extendable arm 39. As withthe previous embodiment, the device includes a distal tip 21 with acentral lumen for a guidewire 33. The distal tip 21 can optionally be adilating tip as described above in the previous embodiment. Also as inthe previous embodiment, the guidewire lumen may extend along the entirelength of the delivery device, such that a guidewire can ride along theentire length of the suture delivery device 5 and exit out the proximalend, or may exit at a point in the delivery shaft distal to the proximalhandle 9.

FIG. 4A shows the device with the extendable arms 39 in the retractedposition. In this configuration, the delivery device 5 may be advancedover a guidewire into an arterial puncture. Once the device is in place,the extendable arms 39 may be extended outward which allows the deviceto be positioned accurately with respect to the vessel wall. FIG. 4Bshows the device with the arms 39 in the extended position, with theends of the suture loop 19 now also extended outwards. The suturecapture rods 15 can now be extended and pierce the vessel wall to eachside of the arterial puncture through which the delivery shaft 7 islocated. The suture capture rods 15 are configured to capture each endof the suture loop 19. When the capture rods 15 are retracted, they drawthe suture loop 19 through the vessel wall across the arterial puncture,until the loop of suture is entirely in the vessel wall and no length ofsuture loop remains in the delivery shaft. The extendable arms 39 cannow be retracted to enable removal of the device from the arterialpuncture.

In a method of use, the ends of the suture 19 are held in tension duringremoval of the suture delivery device 5 while the guidewire 33 remainsin place. A procedural sheath and dilator is then placed over theguidewire and through the pre-placed sutures into the vessel. Theguidewire and dilator are removed, and the procedural sheath remains inplace. The sutures may be relaxed during the subsequent procedure.However, they may be tagged or anchored in some manner so that they maybe grasped and held in tension to achieve rapid hemostasis in the caseof inadvertent sheath removal. After completion of the procedure, thesutures are again held in tension during removal of the proceduralsheath. The ends of the suture are tied and the knot pushed against thearteriotomy to achieve permanent hemostasis.

In an embodiment shown in FIG. 5, a sheath 41 is pre-mounted on thesuture delivery device 5 (which can be any of the embodiments ofdelivery devices described herein). The sheath 41 is an elongated body,such as a tubular body, having an internal lumen sized to receive thedelivery shaft 7 of the suture delivery device 5. The pre-mounted sheath41 is initially positioned in a parked configuration wherein the sheath41 is located on the proximal end or proximal region of the deliveryshaft 7. The sheath 41 can remain in the parked configuration duringsuture placement. After the suture is deployed across the arteriotomy,the ends of the suture are captured and peeled away from the deliveryshaft 7. The sheath 41 can then slide distally over the delivery device5 into the arteriotomy. FIG. 5 shows the pre-mounted sheath beingadvanced after the suture 19 has been placed across the arteriotomy.Alternately, the step of advancing the pre-mounted sheath 41 mayfacilitate peeling away the sutures from the delivery shaft 7 in thatthe sheath 41, as it moves, physically abuts the sutures to cause thesutures to peel away. Once the pre-mounted sheath has been advanced intothe arteriotomy, the delivery device 5 can then be removed through thesheath 41.

In an embodiment, the pre-mounted sheath 41 is an exchange sheath thatprovides a means for maintaining hemostasis of the arteriotomy whileremoving the suture delivery device 5 and then inserting a separateprocedural sheath (such as the arterial access sheath 605 describedbelow) for performing a procedure in the blood vessel. Once the sutureis deployed across the arteriotomy, the exchange sheath 41 is positionedthrough the arteriotomy and then the suture delivery device 5 isremoved. The procedural sheath is then inserted into the blood vesselthrough the exchange sheath 41. Once the procedural sheath is placed,the exchange sheath 41 can be removed. In an embodiment, the exchangesheath 41 is configured to be removed from the procedural sheath in apeel-away fashion. The pre-mounted sheath 41 may have a hemostasis valveeither on its distal end or on its proximal end to prevent bleedingduring this exchange. The hemostasis valve may be in the form of aclosed end or membrane, with a slit or cross slit, or other expandableopening. The membrane is normally closed and opens to allow passage of aprocedural sheath therethrough.

In another embodiment, the pre-mounted sheath 41 is an outer sheathwhich remains in place during the procedure. The outer sheath 41 mayinclude an occlusion element 129, as shown in FIG. 6, that is adapted toincrease in size within the blood vessel to occlude the blood vessel.Once the pre-mounted outer sheath 41 sheath is positioned in the vessel,the procedural sheath is inserted through the outer sheath 41 into theblood vessel. The procedural sheath is then used to introduce one ormore interventional devices into the blood vessel. In an embodiment, theprocedural sheath is a sheath such as the sheath 605 (described below),which is used to connect the blood vessel to a reverse flow shunt, suchas the reverse flow shunt described below. The occlusion element 129 onthe sheath 41 is used to occlude the blood vessel during the procedure.The intravascular occlusion element may be an inflatable balloon, anexpandable member such as a braid, cage, or slotted tube around which isa sealing membrane, or the like. The outer sheath 41 may also include asheath retention element such as an inflatable structure or anexpandable wire, cage, or articulating structure which preventsinadvertent sheath removal when deployed.

This dual sheath configuration allows the pre-mounted sheath to berelatively short compared to the procedural sheath. The proceduralsheath may require an extended proximal section such that the proximaladaptor where interventional devices are introduced into the sheath areat a site distance from the vessel access site, which may beadvantageous in procedures where the vessel access site is near thefluoroscopy field. By keeping the pre-mounted sheath relatively short,the delivery shaft 7 may be kept shorter.

In another embodiment, the pre-mounted sheath 41 is the proceduralsheath itself, such that use of an exchange or outer sheath is notnecessary. The procedural sheath 41 may have a hemostasis valve, such ason the proximal end of the procedural sheath. Thus, when the suturedelivery device 5 is removed, hemostasis is maintained. If a proceduralsheath 41 is used which requires a proximal extended section, anextension can be added to the proximal end of the procedural sheath 41after removal of the suture delivery device 5. Alternately, the deliveryshaft 7 can have an extended length to allow pre-mounting of both theprocedural sheath and proximal extension. The procedural sheath 41 mayinclude an intravascular occlusion element for procedures requiringarterial occlusion. The intravascular occlusion element may be aninflatable balloon, an expandable member such as a braid, cage, orslotted tube around which is a sealing membrane, or the like. Theprocedural sheath may also include a sheath retention element such as aninflatable structure or an expandable wire, cage, or articulatingstructure which prevents inadvertent sheath removal when deployed.

An exemplary method of use of the suture delivery device 5 of FIGS.1A-1C is now described. A puncture is formed into a blood vessel toprovide access to the interior of the vessel. After accessing the bloodvessel, a guidewire is inserted so that the guidewire extends into theskin and down through tissue along tissue tract. The suture deliverydevice 5 is advanced over the guidewire via the guidewire lumen 31 (FIG.2) such that the guidewire directs the suture delivery device 5 alongthe tissue tract and into the vessel through the arteriotomy. Asmentioned, the distal tip of the delivery device acts as a dilator suchthat it dilates the arteriotomy to facilitate entry. The distal tip ofthe delivery device can be used to dilate the arteriotomy without usingany separate dilator device to dilate the arteriotomy. The deliveryshaft 7 includes a position verification lumen. When the vessel walllocator 17 enters the blood vessel, blood flows through the positionverification lumen to the proximal indicator to notify the operator thatthe vessel wall locator has entered the blood vessel.

When the vessel wall locator 17 is positioned inside the blood vessel,the actuation lever 13 on the handle 9 is actuated to move the vesselwall locator 17 to the deployed position inside the blood vessel. Thedeployed vessel wall locator 17 extends laterally from the deliveryshaft 7, so that the vessel wall locator 17 can be drawn up against thevessel wall by pulling the delivery shaft 7.

The actuation handle 11 is then actuated to deploy the suture capturerods 15 toward the vessel wall locator 17. The suture capture rods matewith ends of the flexible link 29 contained in lateral ends of thevessel wall locator 17. This couples at least one end of the suture 19to one end of the flexible link 29, and a suture capture rod 15 to theother end of the flexible link. The suture capture rods 15 can then beused to proximally draw the flexible link, and with it the suture 19,through the vessel wall for forming a suture loop across thearteriotomy. Alternately, the suture capture rods 15 mate directly withends of the suture 19, which are located in the lateral ends of thevessel locator. The suture capture rods 15 are then used to draw theends of the suture 19 through the vessel wall to form a suture loopacross the arteriotomy. The suture capture rods then pull the sutureends out of the tissue tract above the skin, where then may be retrievedby the user.

As the suture ends are held in tension to maintain hemostasis, thesuture delivery device 5 is removed over the guidewire, and exchangedfor the procedure sheath. Manual compression may be applied over thearteriotomy site if needed for additional hemostasis control during theexchange of the suture delivery device 5 for the procedure sheath.

At the conclusion of the procedure, the procedure sheath is removed andthe pre-placed suture ends are knotted and the knot pushed in place, ina similar manner to standard percutaneous suture closure devices. Thesuture ends may be pre-tied in a knot, in which case the knot is simplypushed into place. The tied suture ends are then trimmed.

In variation to this method, the suture delivery device 5 is insertedinto the artery and the sutures are placed across the arteriotomy anddrawn out of the tissue tract and above the skin, where they areretrieved by the user, as described above. The sutures are thenseparated from the delivery shaft 7. Prior suture delivery devices donot allow the sutures to “peel away” from the delivery shaft. Instead,in prior devices, the sutures are pulled out through the proximal end ofthe delivery device. The delivery device 5 disclosed herein permits thesutures to be peeled from the side of the delivery shaft 7. Asmentioned, the sutures and suture capture rods are disposed inopen-sided channels in the delivery shaft 7, as shown in FIGS. 3A and3B. The channels are sized relative to the sutures such that the suturescan be lifted or pulled out of the channels. The suture capture rodsstill exit out the proximal end of the delivery device 5. The suture endthat is attached to the suture capture rod is extracted from thedelivery shaft 7 using a hook or pre-applied loop, and cut free of thesuture capture rods. The other suture end can simply be pulled out ofthe side channels 35. The suture may have a pre-tied knot, as isdisclosed in prior art. In this configuration, the knot must be locatedoutside the body of the patient such that both ends of the suture may begrasped below the knot after the suture ends are retrieved.

With the suture free from the delivery device 5, the delivery device 5can then be removed from the vessel while the guidewire 33 remains inthe vessel. As mentioned, the guidewire channel extends entirely throughthe delivery device 5 to permit the delivery device to be easily removedfrom the guidewire. Prior to removing the delivery device 5, apre-mounted sheath 41 is slid distally from the parked position (on theproximal end of the delivery shaft 7) into the tissue tract and throughthe arteriotomy. The act of pushing the sheath 41 forward can assist inpushing the sutures out of the channels 35 and away from the deliveryshaft 7. As described above, the pre-mounted sheath may be an exchangesheath, an outer sheath for a dual-sheath configuration, or theprocedural sheath itself. The sheath may further contain anintravascular occlusion element.

A variation on this configuration is to insert the suture deliverydevice 5 in the opposite direction from the ultimate direction of thesheath 41. This method may be used if there are anatomic restraints onthe amount of blood vessel which may be entered, for example in atranscervical approach to carotid artery stenosis treatment. In thisretrograde delivery, the delivery device is inserted into the vessel ina more perpendicular approach, so that the tissue tract from the skin tothe artery created by the initial wire puncture and subsequently thesuture delivery device may also be used to approach the artery with theprocedural sheath in the opposite direction. Once the suture has beendeployed and the suture ends have been retrieved, the suture deliverydevice is removed while keeping the guidewire in place. The guidewire isthen re-positioned such that the tip is now in the opposite direction.The guidewire is advanced enough to provide support for the proceduralsheath, which can now be advanced over the guidewire and inserted intothe vessel. As it is critical not to lose the position of the guidewireduring this change in guidewire direction, a feature may be added to theguidewire which prevents it from being removed from the vessel, forexample an expandable element as described below.

In an embodiment, the suture delivery device 5 and the sheath 41 areused to gain access to the common carotid artery pursuant to treatmentof a carotid artery stenosis, or an intracerebral arterial proceduresuch as treatment of acute ischemic stroke, intracerebral arterystenosis, intracerebral aneurysm, or other neurointerventionalprocedure. In an embodiment, transcervical access to the common carotidartery is achieved percutaneously via an incision or puncture in theskin through which the arterial access device 110 is inserted. However,it should be appreciated that the suture delivery device as well as anyof the devices and methods described herein can be used with a varietyof interventional procedures.

In another embodiment, the suture delivery device does not have adilating tip and does not have a premounted sheath. Rather, the suturedelivery device is configured as described, for example, in U.S. Pat.No. 7,001,400. The suture delivery device is used to suture anarteriotomy performed in the common carotid artery via transcervicalaccess. In this embodiment, shown in FIGS. 7A and 7B, the suturedelivery device generally has a shaft 7 having a proximal end 14 and adistal end 16. A proximal housing 18 supports a needle actuation handle20. A flexible, atraumatic monorail guidebody 22 extends distally ofdistal end 16 of shaft 12.

As shown in FIG. 7B, a foot 17 is articulatably mounted near the distalend of shaft 12. The foot 17 moves between a low profile configuration,in which the foot is substantially aligned along an axis of shaft 12 (asillustrated in FIG. 7A), to a deployed position, in which the footextends laterally from the shaft, upon actuation of a foot actuationhandle 26 disposed on proximal housing 18. The suture delivery deviceshown in FIGS. 7A-7B delivers the sutures in a similar manner to the waythat the suture delivery device of FIGS. 1A-1C delivers the suture.

FIG. 8 shows another embodiment of a suture delivery device, generallydesignated 71, for suturing vessel walls and other biological tissue.The device is for use in suturing an arterial vessel walls W. The device71 comprises a suture introducer housing 73 for insertion into anopening O in the arterial wall W. A vessel wall locators in the form ofsuture clasp arms 75, 77 are deployably housed in the housing duringinsertion, and after insertion into the vessel, the arms are deployed tothe position shown in FIG. 8. When deployed, the suture clasp armsextend outside the circumference of the suture introducer housing 73.Each arm has at least one means, generally designated 78 andschematically illustrated, for clasping a suture 19. A penetratingmechanism, generally designated 79, with needles 89 is provided forpenetrating the vessel wall W. The penetrating mechanism is provided oneither the suture introducer housing 73 or on a suture catch assembly,generally designated 80. When, as shown in FIG. 8, the penetratingmechanism is part of the suture catch assembly 80, the penetratingmechanism also comprises a suture catch 81 for catching the suture 19and dislodging it from the clasping means 78. The suture catch assemblyoperates to pull the suture held by the suture catch through the vesselwall. After the ends of the suture are pulled outside the vessel, theintroducing housing can be removed and the suture tied to close thevessel.

In an embodiment shown in FIG. 9, the suture introducer housing 73 is agenerally cylindrical and thin walled hypo tube such as a hollowelongated cylindrical member with a thin wall such that the innerdiameter and outer diameter vary by a relatively small amount in therange of few thousandths of an inch to tens of thousandths of an inch.The outer surface 42 of the housing comprises a key way groove 82(exaggerated for clarity) to align the housing with a key on the innersurface of the suture catch assembly 80 (FIG. 8). An arm actuationassembly 83 for deploying the suture clasp arms protrudes from theproximal end of the housing, and an actuating rod 85 extends from theactuation assembly through the housing to the suture clasp arms. Thesuture delivery device of FIGS. 8 and 9 is described in U.S. Pat. Nos.5,860,990 and 7,004,952, both of which are incorporated by reference intheir entirety.

The suture delivery device of FIGS. 8 and 9 generally works by actuatingan arm on the suture delivery device from a first position wherein thearm is within the suture delivery device to a second position whereinthe arm is extended away from the elongate body. The arm holds a portionof a suture. At least one of the needles 89 is advanced in a proximal todistal direction along at least a portion of the suture delivery devicetoward the arm, the needle being advanced through tissue of the artery.A portion of the needle is engaged with the portion of the suture andthe needle is retracted in a distal to proximal direction to draw thesuture through the artery tissue.

FIG. 10A is a perspective view of an embodiment of a distal region of asuture delivery device with the suture clasp arms 75, 77 partiallydeployed out of apertures 87. FIG. 10B is a perspective view of thesuture delivery device with the suture clasp arms 75, 77 fully deployed.FIG. 10C shows two flexible needles 89 extending out of needle apertures91 and engaging the suture clasp arms 75, 77. The device of FIGS.10A-10C is not shown with a dilating tip although it should beappreciated that the device could be configured with a dilating tippursuant to this disclosure.

The ends of the suture 19 are provided with loops 92 that are configuredto engage with the needles 89. The suture clasp arms 75, 77 eachcomprise an annular recess 93 for holding the suture looped end 92, aslit 94 for the length of the suture 19, and a sloped end 95. Each ofthe flexible needles 89 comprises an extended shaft, a penetratingdistal tip 96, and a groove 97 near the distal tip 96. The needle groove97 acts as a detent mechanism or suture catch. In an embodiment, thegrooves 97 extend around the complete circumference of the needles 89.In other embodiments, the grooves 97 are partially circumferential alongthe radial edge of the needles 89. The loops 92 correspond generally indiameter to grooves 97 of the needles 89, but are sufficiently resilientto expand in diameter in response to the downward force of the needles89.

The general use and operation of the suture clasp arms 75, 77 is nowdescribed. The looped ends 92 of the suture 19 are placed within theannular recess 93 of the suture clasp arms 75, 77. The distal end of thedevice is inserted into biological tissue, and the suture clasp arms 75,77 are deployed radially outward, as shown in FIG. 10B. The penetratingflexible needles 89 pass distally through the biological tissue (e.g.,artery tissue) to be sutured and engage the suture clasp arms 75, 77, asshown in FIG. 10C.

When the distal tips 96 pass through the looped ends 92 of the suture19, the looped ends 92 flex radially outward momentarily. As the needles89 continue to advance distally, the looped ends 92 come in contact withthe grooves 97. The looped ends flex radially inward and fasten aroundthe needle grooves 97, such that pulling the needles 89 proximallycauses the suture ends 92 to follow the proximal movement of the needles89 to draw the suture proximally through the artery tissue.

Additional Embodiments

In another embodiment, the guidewire 33 includes at least one expandablesealing element 43 mounted on the guidewire. The expandable element 43,shown in FIGS. 11A-11C, can expand against the interior vessel wall tomaintain hemostasis of the vessel access site, such as during exchangeof the suture delivery device 5 for the procedural sheath, and duringremoval of procedural sheath. Alternately, the guidewire can be used tomaintain hemostasis if the suture delivery device did not adequatelyplace the suture in the tissue, and the device is needed to be exchangedfor another vessel closure device. The second vessel closure device maybe another suture delivery device, or may be another type of vesselclosure device. This guidewire with sealing element may be used toexchange vessel closure devices either if the sutures are placed beforethe procedural sheath is placed or at the end of the procedure aftersheath removal.

The expandable element 43 can be positioned a predetermined distanceproximal from the distal tip of the guidewire. In an embodiment, theexpandable element 43 is positioned about 3 cm proximal of the distaltip of the guidewire. This ensures that the distal tip of the guidewireis inserted a predetermined distance beyond the expandable element 43.

The expandable element must be collapsed when the suture delivery deviceis inserted into the vessel. The dilator tip 21 of the suture deliverydevice 5 may have an indicator lumen 45 for a blood mark. Thus, as soonas the dilator tip 21 of the delivery device 5 enters the blood vessel,an indication is provided to the operator so that the operator knows todeflate or collapse the expandable element 43 on the guidewire. Theexpandable element 43 can vary in structure. For example, the expandableelement 43 can be a balloon, an expandable member such as a braid, cage,or slotted tube around which is a sealing membrane, or the like.

As shown in FIGS. 11B-11C, the expandable sealing element 43 can bepositioned inside the blood vessel during use. Once the expandableelement 43 is positioned in the blood vessel, the operator can pull itback proximally such that the expandable element 43 is sealed againstthe interior vessel wall. Arterial blood pressure within the vessel willalso help exert pressure of the sealing element against the interiorvessel wall, so that only a small amount of force, if any, may be neededto maintain hemostasis. In another embodiment, shown in FIG. 12, theexpandable element 43 is positioned outside the blood vessel. Theoperator pushes the expandable element forward against the exteriorvessel wall such that the expandable element 43 exerts pressure againstthe exterior vessel wall to achieve and maintain hemostasis.

In yet another embodiment, the guidewire includes a pair of expandablesealing elements 43 a and 43 b, as shown in FIG. 13. During use theblood vessel wall is interposed between the expandable elements 43 a and43 b with the expandable elements 43 exerting pressure on the vesselwall. This advantageously locks the position of the guidewire againstmovement relative to the vessel wall. The expandable elements 43 a and43 b may be spring-loaded toward each other to achieve the pressure onthe vessel wall. In a variation of the multi-expandable elementembodiment, the expandable elements 43 are inflatable balloons. Duringuse, care is taken that expandable portion does not increase the size ofthe arteriotomy, unless it is to be used to “pre-dilate” thearteriotomy.

In another embodiment, the guidewire includes an intravascular anchorthat maintains the position of the guidewire relative to the bloodvessel during insertion of the delivery device 5 and/or the proceduralsheath into the blood vessel. As shown in FIG. 14, the anchor 47 can be,for example, an inflatable balloon, expandable cage or braid, or otherelement that secures to the interior vessel wall. In the case of anexpandable or inflatable anchor 47, the anchor 47 expands to a size suchthat the anchor 47 exerts sufficient force against the vessel wall tosecure the anchor 47 in place.

In an embodiment, the expandable element may serve as both an expandablesealing element and an intravascular anchor. For example if theexpandable element was a balloon, inflation at one diameter may besufficient to create a seal around the arteriotomy as well as anchor theguidewire in the vessel. Alternately, the expandable element is inflatedto one diameter to seal the arteriotomy, and a greater diameter toanchor against the vessel wall. Similarly, a mechanically expandableelement may be expanded to both seal and anchor, or be expanded to onestate sufficient to create a seal, and expanded further to anchoragainst the vessel wall. The device may need to be repositioned betweenthe sealing expansion and the anchor expansion states.

FIG. 15 shows another embodiment wherein the guidewire 33 attaches toone or more clips 51 that can be secured to the skin of the patient tohold the guidewire in place. The clips 51 can be secured to the patientusing various means including an adhesive backing. The clips 51 can bepositioned on the patient's skin in any of a variety of configurations.In the embodiment of FIG. 15, two clips 51 are used including one clip51 a near the entry location into skin and another clip 51 b furtherfrom the entry location. The clips 51 serve to hold the guidewire inplace at all times. The clip 51 b may be released as the delivery device5 device is loaded onto wire, then re-clipped and the clip 51 a isreleased as the delivery device 5 inserted into skin and positioned intothe blood vessel. In a similar fashion, the clips can be used tomaintain the guidewire 33 position while the delivery device is removed,and while the procedural sheath is inserted into the blood vessel.

The clips 51 can also be used for management of the closure suture 19.The clips 51 can include one or more attachment means, such as slots,into which the suture can be inserted and held. FIGS. 16 and 17 show anexample wherein the suture is not pre-tied (FIG. 16) and when the sutureis pre-tied (FIG. 17). The sutures could also be both placed to the sameside of the clip 51. The clips 51 may be configure to hold the suture intension, such as during times when hemostasis is needed to keep suturesin tension to maintain hemostasis until procedural sheath can be placed.In this case, the knot is either not pre-tied or tied but far enoughback that it is outside the skin and both sides of the stitch can beheld in tension. The suture can be held in tension either manually, orwith a clip or cleat on the skin. The suture back end can be attached toa tag or handle, or preattached to the clip or cleat which is thensecured to the skin, to make this process easier. The sutures can eitherbe kept in this clip or cleat during the intervention, or be removed ifthey are in the way, then reinserted after sheath removal but beforeknot tying. Or, the sutures can be manually held in tension and then theknot tied immediately afterwards. Or, if the knot is pre-tied, the knotcan simply pushed down in to place.

In another embodiment, shown in FIGS. 18A-18C, a self-closing material53 is pre-loaded on a proximal region of the delivery shaft 7. A holeextends through the center of the self-closing material and the deliveryshaft 7 is positioned through the hole. The self-closing material isconfigured to automatically close over the hole when the delivery device5 is pulled out of the hole. The self-closing material can be a rubberplug or membrane with a hole, slit, cross slit, duck-bill valve, or acompressible material such as a foam, or simply a pair of spring members(such as a wire or a flat spring) that close over the arteriotomy whenthe device 5 is pulled out. The self-closing material can also be acollagen plug, a bioabsorbable polymer, a non-bioabsorbable polymer suchas Dacron or ePTFE, or other appropriate biocompatible material. If theself-closing material is temporary, the material cab be a softelastomer, such as silicone rubber, or polyurethane.

Just prior to removing the delivery device 5 from the arteriotomy, theself-closing material is pushed distally over the arteriotomy such aswith a pushing element 55 such as push rod or tube, as shown in FIG.18A. The pushing element 55 may be integral to the delivery device 5 orit may be a separate accessory item. The self-closing material is heldin compression over the arteriotomy to maintain hemostasis, as shown inFIG. 18B. The sutures 19 that were just placed, as well as the guidewirewhich remains in place, pass through the center opening of theself-closing material. The procedural sheath is then placed over theguidewire through the self-closing material, through the arteriotomy andinto the blood vessel, as shown in FIG. 18C. The pusher holding theself-closing material in compression against outside of vessel wall canthen be relaxed. After the procedure is completed, the pusher can againbe pushed to apply compression to arteriotomy until a knot is tied inthe suture. Where the pusher is a rigid sleeve, the pusher can double asa means to provide a channel for facilitating device exchange throughtissue tract.

In a variation of this embodiment, the self-closing material remains inplace to act as a hemostasis material at the end of the procedure. Thematerial is pre-loaded on the delivery shaft, and the suture capturerods are threaded through locations to each side of the delivery shaft.Thus when the sutures are pulled out of the delivery shaft, they arealso pulled through two side holes of the self-closing material. Asabove, the material is pushed into place and acts as temporaryhemostasis during device exchange. However, at the end of the procedure,the material remains in place when the suture ends are tied off toachieve permanent hemostasis.

In another embodiment, shown in FIGS. 19A-19C, a hemostasis material 57is positioned over the arteriotomy location after removal of theprocedural sheath. The hemostasis material 57 is placed over the suture19 before the suture knot is tied or during the tying of the sutureknot. The knot secures the hemostasis material in place over thearteriotomy. Alternately, the hemostasis material is inserted over thearteriotomy after the suture knot is tied, and either another tie or aclip can be used to hold the hemostasis material against thearteriotomy. The hemostasis material can be, for example, a collagenplug, a bioabsorbable polymer, a non-bioabsorbable polymer such asDacron or ePTFE, or other appropriate biocompatible material. Thehemostasis material can be a temporary or a permanent material. U.S.Pat. No. 5,549,633, which is incorporated herein by reference in itsentirety, described exemplary devices and methods for coupling a sealingmaterial to a suture.

Reverse Flow System

Any of the embodiments of the suture closure devices discussed above maybe used in combination with a retrograde flow system that may be used inconjunction with a variety of interventional procedures. Exemplaryembodiments of a retrograde flow system and exemplary interventionalprocedures are now described. The system is sometimes described in thecontext of use with a carotid artery stenting procedure although itshould be appreciated that the system can be used with variousprocedures not limited to carotid artery stenting.

FIG. 20 shows a first embodiment of a retrograde flow system 100 that isadapted to establish and facilitate retrograde or reverse flow bloodcirculation in the region of the carotid artery bifurcation in order tolimit or prevent the release of emboli into the cerebral vasculature,particularly into the internal carotid artery. The system 100 interactswith the carotid artery to provide retrograde flow from the carotidartery to a venous return site, such as the internal jugular vein (or toanother return site such as another large vein or an external receptaclein alternate embodiments.) The retrograde flow system 100 includes anarterial access device 110, a venous return device 115, and a shunt 120that provides a passageway for retrograde flow from the arterial accessdevice 110 to the venous return device 115. A flow control assembly 125interacts with the shunt 120. The flow control assembly 125 is adaptedto regulate and/or monitor the retrograde flow from the common carotidartery to the internal jugular vein, as described in more detail below.The flow control assembly 125 interacts with the flow pathway throughthe shunt 120, either external to the flow path, inside the flow path,or both.

The arterial access device 110 at least partially inserts into thecommon carotid artery CCA and the venous return device 115 at leastpartially inserts into a venous return site such as the internal jugularvein IJV, as described in more detail below. The arterial access device110 and the venous return device 115 couple to the shunt 120 atconnection locations 127 a and 127 b. When flow through the commoncarotid artery is blocked, the natural pressure gradient between theinternal carotid artery and the venous system causes blood to flow in aretrograde or reverse direction RG from the cerebral vasculature throughthe internal carotid artery and through the shunt 120 into the venoussystem. The flow control assembly 125 modulates, augments, assists,monitors, and/or otherwise regulates the retrograde blood flow.

In the embodiment of FIG. 20, the arterial access device 110 accessesthe common carotid artery CCA via a transcervical approach.Transcervical access provides a short length and non-tortuous pathwayfrom the vascular access point to the target treatment site therebyeasing the time and difficulty of the procedure, compared for example toa transfemoral approach. Additionally, this access route reduces therisk of emboli generation from navigation of diseased, angulated, ortortuous aortic arch or common carotid artery anatomy. At least aportion of the venous return device 115 is placed in the internaljugular vein IJV. In an embodiment, transcervical access to the commoncarotid artery is achieved percutaneously via an incision or puncture inthe skin through which the arterial access device 110 is inserted. If anincision is used, then the incision can be about 0.5 cm in length. Anocclusion element 129, such as an expandable balloon, can be used toocclude the common carotid artery CCA at a location proximal of thedistal end of the arterial access device 110. The occlusion element 129can be located on the arterial access device 110 or it can be located ona separate device. In an alternate embodiment, the arterial accessdevice 110 accesses the common carotid artery CCA via a direct surgicaltranscervical approach. In the surgical approach, the common carotidartery can be occluded using a tourniquet 2105. The tourniquet 2105 isshown in phantom to indicate that it is a device that is used in theoptional surgical approach.

In another embodiment, shown in the arterial access device 110 accessesthe common carotid artery CCA via a transcervical approach while thevenous return device 115 access a venous return site other than thejugular vein, such as a venous return site comprised of the femoral veinFV. The venous return device 115 can be inserted into a central veinsuch as the femoral vein FV via a percutaneous puncture in the groin.

In another embodiment, the arterial access device 110 accesses thecommon carotid artery via a femoral approach. According to the femoralapproach, the arterial access device 110 approaches the CCA via apercutaneous puncture into the femoral artery FA, such as in the groin,and up the aortic arch AA into the target common carotid artery CCA. Thevenous return device 115 can communicate with the jugular vein JV or thefemoral vein FV.

In another embodiment the system provides retrograde flow from thecarotid artery to an external receptacle 130 rather than to a venousreturn site. The arterial access device 110 connects to the receptacle130 via the shunt 120, which communicates with the flow control assembly125. The retrograde flow of blood is collected in the receptacle 130. Ifdesired, the blood could be filtered and subsequently returned to thepatient. The pressure of the receptacle 130 could be set at zeropressure (atmospheric pressure) or even lower, causing the blood to flowin a reverse direction from the cerebral vasculature to the receptacle130. Optionally, to achieve or enhance reverse flow from the internalcarotid artery, flow from the external carotid artery can be blocked,typically by deploying a balloon or other occlusion element in theexternal carotid artery just above the bifurcation with the internalcarotid artery.

Detailed Description of Retrograde Blood Flow System

As discussed, the retrograde flow system 100 includes the arterialaccess device 110, venous return device 115, and shunt 120 whichprovides a passageway for retrograde flow from the arterial accessdevice 110 to the venous return device 115. The system also includes theflow control assembly 125, which interacts with the shunt 120 toregulate and/or monitor retrograde blood flow through the shunt 120.Exemplary embodiments of the components of the retrograde flow system100 are now described.

Arterial Access Device

FIG. 21A shows an exemplary embodiment of the arterial access device110, which comprises a distal sheath 605, a proximal extension 610, aflow line 615, an adaptor or Y-connector 620, and a hemostasis valve625. The distal sheath 605 is adapted to be introduced through anincision or puncture in a wall of a common carotid artery, either anopen surgical incision or a percutaneous puncture established, forexample, using the Seldinger technique. The length of the sheath can bein the range from 5 to 15 cm, usually being from 10 cm to 12 cm. Theinner diameter is typically in the range from 7 Fr (1 Fr=0.33 mm), to 10Fr, usually being 8 Fr. Particularly when the sheath is being introducedthrough the transcervical approach, above the clavicle but below thecarotid bifurcation, it is desirable that the sheath 605 be highlyflexible while retaining hoop strength to resist kinking and buckling.Thus, the distal sheath 605 can be circumferentially reinforced, such asby braid, helical ribbon, helical wire, or the like. In an alternateembodiment, the distal sheath is adapted to be introduced through apercutaneous puncture into the femoral artery, such as in the groin, andup the aortic arch AA into the target common carotid artery CCA

The distal sheath 605 can have a stepped or other configuration having areduced diameter distal region 630, as shown in FIG. 21B, which shows anenlarged view of the distal region 630 of the sheath 605. The distalregion 630 of the sheath can be sized for insertion into the carotidartery, typically having an inner diameter in the range from 2.16 mm(0.085 inch) to 2.92 mm (0.115 inch) with the remaining proximal regionof the sheath having larger outside and luminal diameters, with theinner diameter typically being in the range from 2.794 mm (0.110 inch)to 3.43 mm (0.135 inch). The larger luminal diameter of the proximalregion minimizes the overall flow resistance of the sheath. In anembodiment, the reduced-diameter distal section 630 has a length ofapproximately 2 cm to 4 cm. The relatively short length of thereduced-diameter distal section 630 permits this section to bepositioned in the common carotid artery CCA via the transcervicalapproach with reduced risk that the distal end of the sheath 605 willcontact the bifurcation B. Moreover, the reduced diameter section 630also permits a reduction in size of the arteriotomy for introducing thesheath 605 into the artery while having a minimal impact in the level offlow resistance.

With reference again to FIG. 21A, the proximal extension 610 has aninner lumen which is contiguous with an inner lumen of the sheath 605.The lumens can be joined by the Y-connector 620 which also connects alumen of the flow line 615 to the sheath. In the assembled system, theflow line 615 connects to and forms a first leg of the retrograde shunt120. The proximal extension 610 can have a length sufficient to spacethe hemostasis valve 625 well away from the Y-connector 620, which isadjacent to the percutaneous or surgical insertion site. By spacing thehemostasis valve 625 away from a percutaneous insertion site, thephysician can introduce a stent delivery system or other workingcatheter into the proximal extension 610 and sheath 605 while stayingout of the fluoroscopic field when fluoroscopy is being performed.

A flush line 635 can be connected to the side of the hemostasis valve625 and can have a stopcock 640 at its proximal or remote end. Theflush-line 635 allows for the introduction of saline, contrast fluid, orthe like, during the procedures. The flush line 635 can also allowpressure monitoring during the procedure. A dilator 645 having a tapereddistal end 650 can be provided to facilitate introduction of the distalsheath 605 into the common carotid artery. The dilator 645 can beintroduced through the hemostasis valve 625 so that the tapered distalend 650 extends through the distal end of the sheath 605, as best seenin FIG. 22A. The dilator 645 can have a central lumen to accommodate aguidewire. Typically, the guidewire is placed first into the vessel, andthe dilator/sheath combination travels over the guidewire as it is beingintroduced into the vessel.

Optionally, a tube 705 may be provided which is coaxially received overthe exterior of the distal sheath 605, also as seen in FIG. 22A. Thetube 705 has a flared proximal end 710 which engages the adapter 620 anda distal end 715. Optionally, the distal end 715 may be beveled, asshown in FIG. 22B. The tube 705 may serve at least two purposes. First,the length of the tube 705 limits the introduction of the sheath 605 tothe exposed distal portion of the sheath 605, as seen in FIG. 22A.Second, the tube 705 can engage a pre-deployed puncture closure devicedisposed in the carotid artery wall, if present, to permit the sheath605 to be withdrawn without dislodging the closure device.

The distal sheath 605 can be configured to establish a curved transitionfrom a generally anterior-posterior approach over the common carotidartery to a generally axial luminal direction within the common carotidartery. The transition in direction is particularly useful when apercutaneous access is provided through the common carotid wall. Whilean open surgical access may allow for some distance in which to angle astraight sheath into the lumen of the common carotid artery,percutaneous access will generally be in a normal or perpendiculardirection relative to the access of the lumen, and in such cases, asheath that can flex or turn at an angle will find great use.

In an embodiment, the sheath 605 includes a retention feature that isadapted to retain the sheath within a blood vessel (such as the commoncarotid artery) into which the sheath 605 has been inserted. Theretention features reduces the likelihood that the sheath 605 will beinadvertently pulled out of the blood vessel. In this regard, theretention feature interacts with the blood vessel to resist and/oreliminate undesired pull-out. In addition, the retention feature mayalso include additional elements that interact with the vessel wall toprevent the sheath from entering too far into the vessel. The retentionfeature may also include sealing elements which help seal the sheathagainst arterial blood pressure at the puncture site.

The sheath 605 can be formed in a variety of ways. For example, thesheath 605 can be pre-shaped to have a curve or an angle some setdistance from the tip, typically 2 to 3 cm. The pre-shaped curve orangle can typically provide for a turn in the range from 20° to 90°,preferably from 30° to 70°. For initial introduction, the sheath 605 canbe straightened with an obturator or other straight or shaped instrumentsuch as the dilator 645 placed into its lumen. After the sheath 605 hasbeen at least partially introduced through the percutaneous or otherarterial wall penetration, the obturator can be withdrawn to allow thesheath 605 to reassume its pre-shaped configuration into the arteriallumen.

Other sheath configurations include having a deflection mechanism suchthat the sheath can be placed and the catheter can be deflected in situto the desired deployment angle. In still other configurations, thecatheter has a non-rigid configuration when placed into the lumen of thecommon carotid artery. Once in place, a pull wire or other stiffeningmechanism can be deployed in order to shape and stiffen the sheath intoits desired configuration. One particular example of such a mechanism iscommonly known as “shape-lock” mechanisms as well described in medicaland patent literature.

Another sheath configuration comprises a curved dilator inserted into astraight but flexible sheath, so that the dilator and sheath are curvedduring insertion. The sheath is flexible enough to conform to theanatomy after dilator removal.

In an embodiment, the sheath has built-in puncturing capability andatraumatic tip analogous to a guide wire tip. This eliminates the needfor needle and wire exchange currently used for arterial accessaccording to the micropuncture technique, and can thus save time, reduceblood loss, and require less surgeon skill.

FIG. 23A shows another embodiment of the arterial access device 110.This embodiment is substantially the same as the embodiment shown inFIG. 21A, except that the distal sheath 605 includes an occlusionelement 129 for occluding flow through, for example the common carotidartery. If the occluding element 129 is an inflatable structure such asa balloon or the like, the sheath 605 can include an inflation lumenthat communicates with the occlusion element 129. The occlusion element129 can be an inflatable balloon, but it could also be an inflatablecuff, a conical or other circumferential element which flares outwardlyto engage the interior wall of the common carotid artery to block flowtherepast, a membrane-covered braid, a slotted tube that radiallyenlarges when axially compressed, or similar structure which can bedeployed by mechanical means, or the like. In the case of balloonocclusion, the balloon can be compliant, non-compliant, elastomeric,reinforced, or have a variety of other characteristics. In anembodiment, the balloon is an elastomeric balloon which is closelyreceived over the exterior of the distal end of the sheath prior toinflation. When inflated, the elastomeric balloon can expand and conformto the inner wall of the common carotid artery. In an embodiment, theelastomeric balloon is able to expand to a diameter at least twice thatof the non-deployed configuration, frequently being able to be deployedto a diameter at least three times that of the undeployed configuration,more preferably being at least four times that of the undeployedconfiguration, or larger.

As shown in FIG. 23B, the distal sheath 605 with the occlusion element129 can have a stepped or other configuration having a reduced diameterdistal region 630. The distal region 630 can be sized for insertion intothe carotid artery with the remaining proximal region of the sheath 605having larger outside and luminal diameters, with the inner diametertypically being in the range from 2.794 mm (0.110 inch) to 3.43 mm(0.135 inch). The larger luminal diameter of the proximal regionminimizes the overall flow resistance of the sheath. In an embodiment,the reduced-diameter distal section 630 has a length of approximately 2cm to 4 cm. The relatively short length of the reduced-diameter distalsection 630 permits this section to be positioned in the common carotidartery CCA via the transcervical approach with reduced risk that thedistal end of the sheath 605 will contact the bifurcation B.

In an embodiment as shown in FIGS. 24 and 25, the proximal extension 610is removably connected to the Y-arm connector 620 at a connection site.In this embodiment, an additional hemostasis valve 621 may be includedat the connection site of the proximal extension 610 to the Y-armconnector 620, so that hemostasis is maintained when the proximalextension is not attached. FIG. 24 shows the arterial access sheath 605,with the proximal extension 610 attached to the Y-connector 620. FIG. 24also shows an additional connection line 623 for balloon inflation of anocclusion element 129. FIG. 25 shows the proximal extension 610 removedfrom the Y-connector 620.

Venous Return Device

Referring now to FIG. 26, the venous return device 115 can comprise adistal sheath 910 and a flow line 915, which connects to and forms a legof the shunt 120 when the system is in use. The distal sheath 910 isadapted to be introduced through an incision or puncture into a venousreturn location, such as the jugular vein or femoral vein. The distalsheath 910 and flow line 915 can be permanently affixed, or can beattached using a conventional luer fitting, as shown in FIG. 26.Optionally, as shown in FIG. 27, the sheath 910 can be joined to theflow line 915 by a Y-connector 1005. The Y-connector 1005 can include ahemostasis valve 1010, permitting insertion of a dilator 1015 tofacilitate introduction of the venous return device into the internaljugular vein or other vein. As with the arterial access dilator 645, thevenous dilator 1015 includes a central guidewire lumen so the venoussheath and dilator combination can be placed over a guidewire.Optionally, the venous sheath 910 can include a flush line 1020 with astopcock 1025 at its proximal or remote end.

In order to reduce the overall system flow resistance, the arterialaccess flow line 615 and the venous return flow line 915, andY-connectors 620 and 1005, can each have a relatively large flow lumeninner diameter, typically being in the range from 2.54 mm (0.100 inch)to 5.08 mm (0.200 inch), and a relatively short length, typically beingin the range from 10 cm to 20 cm. The low system flow resistance isdesirable since it permits the flow to be maximized during portions of aprocedure when the risk of emboli is at its greatest. The low systemflow resistance also allows the use of a variable flow resistance forcontrolling flow in the system, as described in more detail below. Thedimensions of the venous return sheath 910 can be generally the same asthose described for the arterial access sheath 605 above. In the venousreturn sheath, an extension for the hemostasis valve 1010 is notrequired.

Retrograde Shunt

The shunt 120 can be formed of a single tube or multiple, connectedtubes that provide fluid communication between the arterial accesscatheter 110 and the venous return catheter 115 to provide a pathway forretrograde blood flow therebetween. The shunt 120 connects at one end(via connector 127 a) to the flow line 615 of the arterial access device110, and at an opposite end (via connector 127 b) to the flow line 915of the venous return catheter 115.

In an embodiment, the shunt 120 can be formed of at least one tube thatcommunicates with the flow control assembly 125. The shunt 120 can beany structure that provides a fluid pathway for blood flow. The shunt120 can have a single lumen or it can have multiple lumens. The shunt120 can be removably attached to the flow control assembly 125, arterialaccess device 110, and/or venous return device 115. Prior to use, theuser can select a shunt 120 with a length that is most appropriate foruse with the arterial access location and venous return location. In anembodiment, the shunt 120 can include one or more extension tubes thatcan be used to vary the length of the shunt 120. The extension tubes canbe modularly attached to the shunt 120 to achieve a desired length. Themodular aspect of the shunt 120 permits the user to lengthen the shunt120 as needed depending on the site of venous return. For example, insome patients, the internal jugular vein IJV is small and/or tortuous.The risk of complications at this site may be higher than at some otherlocations, due to proximity to other anatomic structures. In addition,hematoma in the neck may lead to airway obstruction and/or cerebralvascular complications. Consequently, for such patients it may bedesirable to locate the venous return site at a location other than theinternal jugular vein IJV, such as the femoral vein. A femoral veinreturn site may be accomplished percutaneously, with lower risk ofserious complication, and also offers an alternative venous access tothe central vein if the internal jugular vein IJV is not available.Furthermore, the femoral venous return changes the layout of the reverseflow shunt such that the shunt controls may be located closer to the“working area” of the intervention, where the devices are beingintroduced and the contrast injection port is located.

In an embodiment, the shunt 120 has an internal diameter of 4.76 mm (3/16 inch) and has a length of 40-70 cm. As mentioned, the length of theshunt can be adjusted.

Flow Control Assembly—Regulation and Monitoring of Retrograde Flow

The flow control assembly 125 interacts with the retrograde shunt 120 toregulate and/or monitor the retrograde flow rate from the common carotidartery to the venous return site, such as the internal jugular vein, orto the external receptacle 130. In this regard, the flow controlassembly 125 enables the user to achieve higher maximum flow rates thanexisting systems and to also selectively adjust, set, or otherwisemodulate the retrograde flow rate. Various mechanisms can be used toregulate the retrograde flow rate, as described more fully below. Theflow control assembly 125 enables the user to configure retrograde bloodflow in a manner that is suited for various treatment regimens, asdescribed below.

In general, the ability to control the continuous retrograde flow rateallows the physician to adjust the protocol for individual patients andstages of the procedure. The retrograde blood flow rate will typicallybe controlled over a range from a low rate to a high rate. The high ratecan be at least two fold higher than the low rate, typically being atleast three fold higher than the low rate, and often being at least fivefold higher than the low rate, or even higher. In an embodiment, thehigh rate is at least three fold higher than the low rate and in anotherembodiment the high rate is at least six fold higher than the low rate.While it is generally desirable to have a high retrograde blood flowrate to maximize the extraction of emboli from the carotid arteries, theability of patients to tolerate retrograde blood flow will vary. Thus,by having a system and protocol which allows the retrograde blood flowrate to be easily modulated, the treating physician can determine whenthe flow rate exceeds the tolerable level for that patient and set thereverse flow rate accordingly. For patients who cannot toleratecontinuous high reverse flow rates, the physician can chose to turn onhigh flow only for brief, critical portions of the procedure when therisk of embolic debris is highest. At short intervals, for examplebetween 15 seconds and 1 minute, patient tolerance limitations areusually not a factor.

In specific embodiments, the continuous retrograde blood flow rate canbe controlled at a base line flow rate in the range from 10 ml/min to200 ml/min, typically from 20 ml/min to 100 ml/min. These flow rateswill be tolerable to the majority of patients. Although flow rate ismaintained at the base line flow rate during most of the procedure, attimes when the risk of emboli release is increased, the flow rate can beincreased above the base line for a short duration in order to improvethe ability to capture such emboli. For example, the retrograde bloodflow rate can be increased above the base line when the stent catheteris being introduced, when the stent is being deployed, pre- andpost-dilatation of the stent, removal of the common carotid arteryocclusion, and the like.

The flow rate control system can be cycled between a relatively low flowrate and a relatively high flow rate in order to “flush” the carotidarteries in the region of the carotid bifurcation prior toreestablishing antegrade flow. Such cycling can be established with ahigh flow rate which can be approximately two to six fold greater thanthe low flow rate, typically being about three fold greater. The cyclescan typically have a length in the range from 0.5 seconds to 10 seconds,usually from 2 seconds to 5 seconds, with the total duration of thecycling being in the range from 5 seconds to 60 seconds, usually from 10seconds to 30 seconds.

FIG. 28 shows an example of the system 100 with a schematicrepresentation of the flow control assembly 125, which is positionedalong the shunt 120 such that retrograde blood flow passes through orotherwise communicates with at least a portion of the flow controlassembly 125. The flow control assembly 125 can include variouscontrollable mechanisms for regulating and/or monitoring retrogradeflow. The mechanisms can include various means of controlling theretrograde flow, including one or more pumps 1110, valves 1115, syringes1120 and/or a variable resistance component 1125. The flow controlassembly 125 can be manually controlled by a user and/or automaticallycontrolled via a controller 1130 to vary the flow through the shunt 120.For example, varying the flow resistance, the rate of retrograde bloodflow through the shunt 120 can be controlled. The controller 1130, whichis described in more detail below, can be integrated into the flowcontrol assembly 125 or it can be a separate component that communicateswith the components of the flow control assembly 125.

In addition, the flow control assembly 125 can include one or more flowsensors 1135 and/or anatomical data sensors 1140 (described in detailbelow) for sensing one or more aspects of the retrograde flow. A filter1145 can be positioned along the shunt 120 for removing emboli beforethe blood is returned to the venous return site. When the filter 1145 ispositioned upstream of the controller 1130, the filter 1145 can preventemboli from entering the controller 1145 and potentially clogging thevariable flow resistance component 1125. It should be appreciated thatthe various components of the flow control assembly 125 (including thepump 1110, valves 1115, syringes 1120, variable resistance component1125, sensors 1135/1140, and filter 1145) can be positioned at variouslocations along the shunt 120 and at various upstream or downstreamlocations relative to one another. The components of the flow controlassembly 125 are not limited to the locations shown in FIG. 28.Moreover, the flow control assembly 125 does not necessarily include allof the components but can rather include various sub-combinations of thecomponents. For example, a syringe could optionally be used within theflow control assembly 125 for purposes of regulating flow or it could beused outside of the assembly for purposes other than flow regulation,such as to introduce fluid such as radiopaque contrast into the arteryin an antegrade direction via the shunt 120.

Both the variable resistance component 1125 and the pump 1110 can becoupled to the shunt 120 to control the retrograde flow rate. Thevariable resistance component 1125 controls the flow resistance, whilethe pump 1110 provides for positive displacement of the blood throughthe shunt 120. Thus, the pump can be activated to drive the retrogradeflow rather than relying on the perfusion stump pressures of the ECA andICA and the venous back pressure to drive the retrograde flow. The pump1110 can be a peristaltic tube pump or any type of pump including apositive displacement pump. The pump 1110 can be activated anddeactivated (either manually or automatically via the controller 1130)to selectively achieve blood displacement through the shunt 120 and tocontrol the flow rate through the shunt 120. Displacement of the bloodthrough the shunt 120 can also be achieved in other manners includingusing the aspiration syringe 1120, or a suction source such as avacutainer, vaculock syringe, or wall suction may be used. The pump 1110can communicate with the controller 1130.

One or more flow control valves 1115 can be positioned along the pathwayof the shunt. The valve(s) can be manually actuated or automaticallyactuated (via the controller 1130). The flow control valves 1115 can be,for example one-way valves to prevent flow in the antegrade direction inthe shunt 120, check valves, or high pressure valves which would closeoff the shunt 120, for example during high-pressure contrast injections(which are intended to enter the arterial vasculature in an antegradedirection).

The controller 1130 communicates with components of the system 100including the flow control assembly 125 to enable manual and/orautomatic regulation and/or monitoring of the retrograde flow throughthe components of the system 100 (including, for example, the shunt 120,the arterial access device 110, the venous return device 115 and theflow control assembly 125). For example, a user can actuate one or moreactuators on the controller 1130 to manually control the components ofthe flow control assembly 125. Manual controls can include switches ordials or similar components located directly on the controller 1130 orcomponents located remote from the controller 1130 such as a foot pedalor similar device. The controller 1130 can also automatically controlthe components of the system 100 without requiring input from the user.In an embodiment, the user can program software in the controller 1130to enable such automatic control. The controller 1130 can controlactuation of the mechanical portions of the flow control assembly 125.The controller 1130 can include circuitry or programming that interpretssignals generated by sensors 1135/1140 such that the controller 1130 cancontrol actuation of the flow control assembly 125 in response to suchsignals generated by the sensors.

The representation of the controller 1130 in FIG. 28 is merelyexemplary. It should be appreciated that the controller 1130 can vary inappearance and structure. The controller 1130 is shown in FIG. 28 asbeing integrated in a single housing. This permits the user to controlthe flow control assembly 125 from a single location. It should beappreciated that any of the components of the controller 1130 can beseparated into separate housings. Further, FIG. 28 shows the controller1130 and flow control assembly 125 as separate housings. It should beappreciated that the controller 1130 and flow control regulator 125 canbe integrated into a single housing or can be divided into multiplehousings or components.

Flow State Indicator(s)

The controller 1130 can include one or more indicators that provides avisual and/or audio signal to the user regarding the state of theretrograde flow. An audio indication advantageously reminds the user ofa flow state without requiring the user to visually check the flowcontroller 1130. The indicator(s) can include a speaker 1150 and/or alight 1155 or any other means for communicating the state of retrogradeflow to the user. The controller 1130 can communicate with one or moresensors of the system to control activation of the indicator. Or,activation of the indicator can be tied directly to the user actuatingone of the flow control actuators 1165. The indicator need not be aspeaker or a light. The indicator could simply be a button or switchthat visually indicates the state of the retrograde flow. For example,the button being in a certain state (such as a pressed or down state)may be a visual indication that the retrograde flow is in a high state.Or, a switch or dial pointing toward a particular labeled flow state maybe a visual indication that the retrograde flow is in the labeled state.

The indicator can provide a signal indicative of one or more states ofthe retrograde flow. In an embodiment, the indicator identifies only twodiscrete states: a state of “high” flow rate and a state of “low” flowrate. In another embodiment, the indicator identifies more than two flowrates, including a “high” flow rate, a “medium” flow rate, and a “low”rate. The indicator can be configured to identify any quantity ofdiscrete states of the retrograde flow or it can identify a graduatedsignal that corresponds to the state of the retrograde flow. In thisregard, the indicator can be a digital or analog meter 1160 thatindicates a value of the retrograde flow rate, such as in ml/min or anyother units.

In an embodiment, the indicator is configured to indicate to the userwhether the retrograde flow rate is in a state of “high” flow rate or a“low” flow rate. For example, the indicator may illuminate in a firstmanner (e.g., level of brightness) and/or emit a first audio signal whenthe flow rate is high and then change to a second manner of illuminationand/or emit a second audio signal when the flow rate is low. Or, theindicator may illuminate and/or emit an audio signal only when the flowrate is high, or only when the flow rate is low. Given that somepatients may be intolerant of a high flow rate or intolerant of a highflow rate beyond an extended period of time, it can be desirable thatthe indicator provide notification to the user when the flow rate is inthe high state. This would serve as a fail safe feature.

In another embodiment, the indicator provides a signal (audio and/orvisual) when the flow rate changes state, such as when the flow ratechanges from high to low and/or vice-versa. In another embodiment, theindicator provides a signal when no retrograde flow is present, such aswhen the shunt 120 is blocked or one of the stopcocks in the shunt 120is closed.

Flow Rate Actuators

The controller 1130 can include one or more actuators that the user canpress, switch, manipulate, or otherwise actuate to regulate theretrograde flow rate and/or to monitor the flow rate. For example, thecontroller 1130 can include a flow control actuator 1165 (such as one ormore buttons, knobs, dials, switches, etc.) that the user can actuate tocause the controller to selectively vary an aspect of the reverse flow.For example, in the illustrated embodiment, the flow control actuator1165 is a knob that can be turned to various discrete positions each ofwhich corresponds to the controller 1130 causing the system 100 toachieve a particular retrograde flow state. The states include, forexample, (a) OFF; (b) LO-FLOW; (c) HI-FLOW; and (d) ASPIRATE. It shouldbe appreciated that the foregoing states are merely exemplary and thatdifferent states or combinations of states can be used. The controller1130 achieves the various retrograde flow states by interacting with oneor more components of the system, including the sensor(s), valve(s),variable resistance component, and/or pump(s). It should be appreciatedthat the controller 1130 can also include circuitry and software thatregulates the retrograde flow rate and/or monitors the flow rate suchthat the user wouldn't need to actively actuate the controller 1130.

The OFF state corresponds to a state where there is no retrograde bloodflow through the shunt 120. When the user sets the flow control actuator1165 to OFF, the controller 1130 causes the retrograde flow to cease,such as by shutting off valves or closing a stop cock in the shunt 120.The LO-FLOW and HI-FLOW states correspond to a low retrograde flow rateand a high retrograde flow rate, respectively. When the user sets theflow control actuator 1165 to LO-FLOW or HI-FLOW, the controller 1130interacts with components of the flow control regulator 125 includingpump(s) 1110, valve(s) 1115 and/or variable resistance component 1125 toincrease or decrease the flow rate accordingly. Finally, the ASPIRATEstate corresponds to opening the circuit to a suction source, forexample a vacutainer or suction unit, if active retrograde flow isdesired.

The system can be used to vary the blood flow between various statesincluding an active state, a passive state, an aspiration state, and anoff state. The active state corresponds to the system using a means thatactively drives retrograde blood flow. Such active means can include,for example, a pump, syringe, vacuum source, etc. The passive statecorresponds to when retrograde blood flow is driven by the perfusionstump pressures of the ECA and ICA and possibly the venous pressure. Theaspiration state corresponds to the system using a suction source, forexample a vacutainer or suction unit, to drive retrograde blood flow.The off state corresponds to the system having zero retrograde bloodflow such as the result of closing a stopcock or valve. The low and highflow rates can be either passive or active flow states. In anembodiment, the particular value (such as in ml/min) of either the lowflow rate and/or the high flow rate can be predetermined and/orpre-programmed into the controller such that the user does not actuallyset or input the value. Rather, the user simply selects “high flow”and/or “low flow” (such as by pressing an actuator such as a button onthe controller 1130) and the controller 1130 interacts with one or moreof the components of the flow control assembly 125 to cause the flowrate to achieve the predetermined high or low flow rate value. Inanother embodiment, the user sets or inputs a value for low flow rateand/or high flow rate such as into the controller. In anotherembodiment, the low flow rate and/or high flow rate is not actually set.Rather, external data (such as data from the anatomical data sensor1140) is used as the basis for affects the flow rate.

The flow control actuator 1165 can be multiple actuators, for exampleone actuator, such as a button or switch, to switch state from LO-FLOWto HI-FLOW and another to close the flow loop to OFF, for example duringa contrast injection where the contrast is directed antegrade into thecarotid artery. In an embodiment, the flow control actuator 1165 caninclude multiple actuators. For example, one actuator can be operated toswitch flow rate from low to high, another actuator can be operated totemporarily stop flow, and a third actuator (such as a stopcock) can beoperated for aspiration using a syringe. In another example, oneactuator is operated to switch to LO-FLOW and another actuator isoperated to switch to HI-FLOW. Or, the flow control actuator 1165 caninclude multiple actuators to switch states from LO-FLOW to HI-FLOW andadditional actuators for fine-tuning flow rate within the high flowstate and low flow state. Upon switching between LO-FLOW and HI-FLOW,these additional actuators can be used to fine-tune the flow rateswithin those states. Thus, it should be appreciated that within eachstate (i.e. high flow state and low flow states) a variety of flow ratescan be dialed in and fine-tuned. A wide variety of actuators can be usedto achieve control over the state of flow.

The controller 1130 or individual components of the controller 1130 canbe located at various positions relative to the patient and/or relativeto the other components of the system 100. For example, the flow controlactuator 1165 can be located near the hemostasis valve where anyinterventional tools are introduced into the patient in order tofacilitate access to the flow control actuator 1165 during introductionof the tools. The location may vary, for example, based on whether atransfemoral or a transcervical approach is used. The controller 1130can have a wireless connection to the remainder of the system 100 and/ora wired connection of adjustable length to permit remote control of thesystem 100. The controller 1130 can have a wireless connection with theflow control regulator 125 and/or a wired connection of adjustablelength to permit remote control of the flow control regulator 125. Thecontroller 1130 can also be integrated in the flow control regulator125. Where the controller 1130 is mechanically connected to thecomponents of the flow control assembly 125, a tether with mechanicalactuation capabilities can connect the controller 1130 to one or more ofthe components. In an embodiment, the controller 1130 can be positioneda sufficient distance from the system 100 to permit positioning thecontroller 1130 outside of a radiation field when fluoroscopy is in use.

The controller 1130 and any of its components can interact with othercomponents of the system (such as the pump(s), sensor(s), shunt, etc) invarious manners. For example, any of a variety of mechanical connectionscan be used to enable communication between the controller 1130 and thesystem components. Alternately, the controller 1130 can communicateelectronically or magnetically with the system components.Electro-mechanical connections can also be used. The controller 1130 canbe equipped with control software that enables the controller toimplement control functions with the system components. The controlleritself can be a mechanical, electrical or electro-mechanical device. Thecontroller can be mechanically, pneumatically, or hydraulically actuatedor electromechanically actuated (for example in the case of solenoidactuation of flow control state). The controller 1130 can include acomputer, computer processor, and memory, as well as data storagecapabilities.

Sensor(s)

As mentioned, the flow control assembly 125 can include or interact withone or more sensors, which communicate with the system 100 and/orcommunicate with the patient's anatomy. Each of the sensors can beadapted to respond to a physical stimulus (including, for example, heat,light, sound, pressure, magnetism, motion, etc.) and to transmit aresulting signal for measurement or display or for operating thecontroller 1130. In an embodiment, the flow sensor 1135 interacts withthe shunt 120 to sense an aspect of the flow through the shunt 120, suchas flow velocity or volumetric rate of blood flow. The flow sensor 1135could be directly coupled to a display that directly displays the valueof the volumetric flow rate or the flow velocity. Or the flow sensor1135 could feed data to the controller 1130 for display of thevolumetric flow rate or the flow velocity.

The type of flow sensor 1135 can vary. The flow sensor 1135 can be amechanical device, such as a paddle wheel, flapper valve, rolling ball,or any mechanical component that responds to the flow through the shunt120. Movement of the mechanical device in response to flow through theshunt 120 can serve as a visual indication of fluid flow and can also becalibrated to a scale as a visual indication of fluid flow rate. Themechanical device can be coupled to an electrical component. Forexample, a paddle wheel can be positioned in the shunt 120 such thatfluid flow causes the paddle wheel to rotate, with greater rate of fluidflow causing a greater speed of rotation of the paddle wheel. The paddlewheel can be coupled magnetically to a Hall-effect sensor to detect thespeed of rotation, which is indicative of the fluid flow rate throughthe shunt 120.

In an embodiment, the flow sensor 1135 is an ultrasonic orelectromagnetic flow meter, which allows for blood flow measurementwithout contacting the blood through the wall of the shunt 120. Anultrasonic or electromagnetic flow meter can be configured such that itdoes not have to contact the internal lumen of the shunt 120. In anembodiment, the flow sensor 1135 at least partially includes a Dopplerflow meter, such as a Transonic flow meter, that measures fluid flowthrough the shunt 120. It should be appreciated that any of a widevariety of sensor types can be used including an ultrasound flow meterand transducer. Moreover, the system can include multiple sensors.

The system 100 is not limited to using a flow sensor 1135 that ispositioned in the shunt 120 or a sensor that interacts with the venousreturn device 115 or the arterial access device 110. For example, ananatomical data sensor 1140 can communicate with or otherwise interactwith the patient's anatomy such as the patient's neurological anatomy.In this manner, the anatomical data sensor 1140 can sense a measurableanatomical aspect that is directly or indirectly related to the rate ofretrograde flow from the carotid artery. For example, the anatomicaldata sensor 1140 can measure blood flow conditions in the brain, forexample the flow velocity in the middle cerebral artery, and communicatesuch conditions to a display and/or to the controller 1130 foradjustment of the retrograde flow rate based on predetermined criteria.In an embodiment, the anatomical data sensor 1140 comprises atranscranial Doppler ultrasonography (TCD), which is an ultrasound testthat uses reflected sound waves to evaluate blood as it flows throughthe brain. Use of TCD results in a TCD signal that can be communicatedto the controller 1130 for controlling the retrograde flow rate toachieve or maintain a desired TCD profile. The anatomical data sensor1140 can be based on any physiological measurement, including reverseflow rate, blood flow through the middle cerebral artery, TCD signals ofembolic particles, or other neuromonitoring signals.

In an embodiment, the system 100 comprises a closed-loop control system.In the closed-loop control system, one or more of the sensors (such asthe flow sensor 1135 or the anatomical data sensor 1140) senses ormonitors a predetermined aspect of the system 100 or the anatomy (suchas, for example, reverse flow rate and/or neuromonitoring signal). Thesensor(s) feed relevant data to the controller 1130, which continuouslyadjusts an aspect of the system as necessary to maintain a desiredretrograde flow rate. The sensors communicate feedback on how the system100 is operating to the controller 1130 so that the controller 1130 cantranslate that data and actuate the components of the flow controlregulator 125 to dynamically compensate for disturbances to theretrograde flow rate. For example, the controller 1130 may includesoftware that causes the controller 1130 to signal the components of theflow control assembly 125 to adjust the flow rate such that the flowrate is maintained at a constant state despite differing blood pressuresfrom the patient. In this embodiment, the system 100 need not rely onthe user to determine when, how long, and/or what value to set thereverse flow rate in either a high or low state. Rather, software in thecontroller 1130 can govern such factors. In the closed loop system, thecontroller 1130 can control the components of the flow control assembly125 to establish the level or state of retrograde flow (either analoglevel or discreet state such as high, low, baseline, medium, etc.) basedon the retrograde flow rate sensed by the sensor 1135.

In an embodiment, the anatomical data sensor 1140 (which measures aphysiologic measurement in the patient) communicates a signal to thecontroller 1130, which adjusts the flow rate based on the signal. Forexample the physiological measurement may be based on flow velocitythrough the MCA, TCD signal, or some other cerebral vascular signal. Inthe case of the TCD signal, TCD may be used to monitor cerebral flowchanges and to detect microemboli. The controller 1130 may adjust theflow rate to maintain the TCD signal within a desired profile. Forexample, the TCD signal may indicate the presence of microemboli (“TCDhits”) and the controller 1130 can adjust the retrograde flow rate tomaintain the TCD hits below a threshold value of hits. (See, Ribo, etal., “Transcranial Doppler Monitoring of Transcervical Carotid Stentingwith Flow Reversal Protection: A Novel Carotid RevascularizationTechnique”, Stroke 2006, 37, 2846-2849; Shekel, et al., “Experience of500 Cases of Neurophysiological Monitoring in Carotid Endarterectomy”,Acta Neurochir, 2007, 149:681-689, which are incorporated by referencein their entirety.

In the case of the MCA flow, the controller 1130 can set the retrogradeflow rate at the “maximum” flow rate that is tolerated by the patient,as assessed by perfusion to the brain. The controller 1130 can thuscontrol the reverse flow rate to optimize the level of protection forthe patient without relying on the user to intercede. In anotherembodiment, the feedback is based on a state of the devices in thesystem 100 or the interventional tools being used. For example, a sensormay notify the controller 1130 when the system 100 is in a high riskstate, such as when an interventional catheter is positioned in thesheath 605. The controller 1130 then adjusts the flow rate to compensatefor such a state.

The controller 1130 can be used to selectively augment the retrogradeflow in a variety of manners. For example, it has been observed thatgreater reverse flow rates may cause a resultant greater drop in bloodflow to the brain, most importantly the ipsilateral MCA, which may notbe compensated enough with collateral flow from the Circle of Willis.Thus a higher reverse flow rate for an extended period of time may leadto conditions where the patient's brain is not getting enough bloodflow, leading to patient intolerance as exhibited by neurologicsymptoms. Studies show that MCA blood velocity less than 10 cm/sec is athreshold value below which patient is at risk for neurological blooddeficit. There are other markers for monitoring adequate perfusion tothe brains, such as EEG signals. However, a high flow rate may betolerated even up to a complete stoppage of MCA flow for a short period,up to about 15 seconds to 1 minute.

Thus, the controller 1130 can optimize embolic debris capture byautomatically increasing the reverse flow only during limited timeperiods which correspond to periods of heightened risk of emboligeneration during a procedure. These periods of heightened risk includethe period of time while an interventional device (such as a dilatationballoon for pre or post stenting dilatation or a stent delivery device)crosses the plaque P. Another period is during an interventionalmaneuver such as deployment of the stent or inflation and deflation ofthe balloon pre- or post-dilatation. A third period is during injectionof contrast for angiographic imaging of treatment area. During lowerrisk periods, the controller can cause the reverse flow rate to revertto a lower, baseline level. This lower level may correspond to a lowreverse flow rate in the ICA, or even slight antegrade flow in thosepatients with a high ECA to ICA perfusion pressure ratio.

In a flow regulation system where the user manually sets the state offlow, there is risk that the user may not pay attention to the state ofretrograde flow (high or low) and accidentally keep the circuit on highflow. This may then lead to adverse patient reactions. In an embodiment,as a safety mechanism, the default flow rate is the low flow rate. Thisserves as a fail safe measure for patient's that are intolerant of ahigh flow rate. In this regard, the controller 1130 can be biased towardthe default rate such that the controller causes the system to revert tothe low flow rate after passage of a predetermined period of time ofhigh flow rate. The bias toward low flow rate can be achieved viaelectronics or software, or it can be achieved using mechanicalcomponents, or a combination thereof. In an embodiment, the flow controlactuator 1165 of the controller 1130 and/or valve(s) 1115 and/or pump(s)1110 of the flow control regulator 125 are spring loaded toward a statethat achieves a low flow rate. The controller 1130 is configured suchthat the user may over-ride the controller 1130 such as to manuallycause the system to revert to a state of low flow rate if desired.

In another safety mechanism, the controller 1130 includes a timer 1170(FIG. 28) that keeps time with respect to how long the flow rate hasbeen at a high flow rate. The controller 1130 can be programmed toautomatically cause the system 100 to revert to a low flow rate after apredetermined time period of high flow rate, for example after 15, 30,or 60 seconds or more of high flow rate. After the controller reverts tothe low flow rate, the user can initiate another predetermined period ofhigh flow rate as desired. Moreover, the user can override thecontroller 1130 to cause the system 100 to move to the low flow rate (orhigh flow rate) as desired.

In an exemplary procedure, embolic debris capture is optimized while notcausing patient tolerance issues by initially setting the level ofretrograde flow at a low rate, and then switching to a high rate fordiscreet periods of time during critical stages in the procedure.Alternately, the flow rate is initially set at a high rate, and thenverifying patient tolerance to that level before proceeding with therest of the procedure. If the patient shows signs of intolerance, theretrograde flow rate is lowered. Patient tolerance may be determinedautomatically by the controller based on feedback from the anatomicaldata sensor 1140 or it may be determined by a user based on patientobservation. The adjustments to the retrograde flow rate may beperformed automatically by the controller or manually by the user.Alternately, the user may monitor the flow velocity through the middlecerebral artery (MCA), for example using TCD, and then to set themaximum level of reverse flow which keeps the MCA flow velocity abovethe threshold level. In this situation, the entire procedure may be donewithout modifying the state of flow. Adjustments may be made as neededif the MCA flow velocity changes during the course of the procedure, orthe patient exhibits neurologic symptoms.

Exemplary Mechanisms to Regulate Flow

The system 100 is adapted to regulate retrograde flow in a variety ofmanners. Any combination of the pump 1110, valve 1115, syringe 1120,and/or variable resistance component 1125 can be manually controlled bythe user or automatically controlled via the controller 1130 to adjustthe retrograde flow rate. Thus, the system 100 can regulate retrogradeflow in various manners, including controlling an active flow component(e.g., pump, syringe, etc.), reducing the flow restriction, switching toan aspiration source (such as a pre-set VacLock syringe, Vacutainer,suction system, or the like), or any combination thereof.

In the situation where an external receptacle or reservoir is used, theretrograde flow may be augmented in various manners. The reservoir has ahead height comprised of the height of the blood inside the reservoirand the height of the reservoir with respect to the patient. Reverseflow into the reservoir may be modulated by setting the reservoir heightto increase or decrease the amount of pressure gradient from the CCA tothe reservoir. In an embodiment, the reservoir is raised to increase thereservoir pressure to a pressure that is greater than venous pressure.Or, the reservoir can be positioned below the patient, such as down to alevel of the floor, to lower the reservoir pressure to a pressure belowvenous or atmospheric pressure.

The variable flow resistance in shunt 120 may be provided in a widevariety of ways. In this regard, flow resistance component 1125 cancause a change in the size or shape of the shunt to vary flow conditionsand thereby vary the flow rate. Or, the flow resistance component 1125can re-route the blood flow through one or more alternate flow pathwaysin the shunt to vary the flow conditions. Some exemplary embodiments ofthe flow resistance component 1125 are now described.

As shown in FIGS. 29A, 29B, 29C, and 29D, in an embodiment the shunt 120has an inflatable bladder 1205 formed along a portion of its interiorlumen. As shown in FIGS. 29A and 29C, when the bladder 1205 is deflated,the inner lumen of the shunt 120 remains substantially unrestricted,providing for a low resistance flow. By inflating the bladder 1205,however, as shown in FIGS. 29B and 29D, the flow lumen can be greatlyrestricted, thus greatly increasing the flow resistance and reducing theflow rate of atrial blood to the venous vasculature. The controller 1130can control inflation/deflation of the bladder 1205 or it can becontrolled manually by the user.

Rather than using an inflatable internal bladder, as shown in FIGS.29A-29D, the cross-sectional area of the lumen in the shunt 120 may bedecreased by applying an external force, such as flattening the shunt120 with a pair of opposed plates 1405, as shown in FIGS. 30A-30D. Theopposed plates are adapted to move toward and away from one another withthe shunt 120 positioned between the plates. When the plates 1405 arespaced apart, as shown in FIGS. 30A and 30C, the lumen of the shunt 120remains unrestricted. When the plates 1405 are closed on the shunt 120,as shown in FIGS. 30B and 30D, in contrast, the plates 1405 constrictthe shunt 120. In this manner, the lumen remaining in shunt 120 can begreatly decreased to increase flow resistance through the shunt. Thecontroller 1130 can control movement of the plates 1405 or such movementcan be controlled manually by the user.

Referring now to FIGS. 31A and 31B, the available cross-sectional areaof the shunt 120 can also be restricted by axially elongating a portion1505 of the shunt 120. Prior to axial elongation, the portion 1505 willbe generally unchanged, providing a full luminal flow area in theportion 1505, as shown in FIG. 31A. By elongating the portion 1505,however, as shown in FIG. 31B, the internal luminal area of the shunt120 in the portion 1505 can be significantly decreased and the lengthincreased, both of which have the effect of increasing the flowresistance. When employing axial elongation to reduce the luminal areaof shunt 120, it will be advantageous to employ a mesh or braidstructure in the shunt at least in the portion 1505. The mesh or braidstructure provides the shunt 120 with a pliable feature that facilitatesaxial elongation without breaking. The controller 1130 can controlelongation of the shunt 120 or such it can be controlled manually by theuser.

Referring now to FIGS. 32A-32D, instead of applying an external force toreduce the cross-sectional area of shunt 120, a portion of the shunt 120can be made with a small diameter to begin with, as shown in FIGS. 32Aand 32C. The shunt 120 passes through a chamber 1600 which is sealed atboth ends. A vacuum is applied within the chamber 1600 exterior of theshunt 120 to cause a pressure gradient. The pressure gradient cause theshunt 120 to increase in size within the chamber 120, as shown in FIGS.32B and 32D. The vacuum may be applied in a receptacle 1605 attached toa vacuum source 1610. Conversely, a similar system may be employed witha shunt 120 whose resting configuration is in the increased size.Pressure may be applied to the chamber to shrink or flatten the shunt todecrease the flow resistance. The controller 1130 can control the vacuumor it can be controlled manually by the user.

As yet another alternative, the flow resistance through shunt 120 may bechanged by providing two or more alternative flow paths. As shown inFIG. 33A, the flow through shunt 120 passes through a main lumen 1700 aswell as secondary lumen 1705. The secondary lumen 1705 is longer and/orhas a smaller diameter than the main lumen 1700. Thus, the secondarylumen 1705 has higher flow resistance than the main lumen 1700. Bypassing the blood through both these lumens, the flow resistance will beat a minimum. Blood is able to flow through both lumens 1700 and 1705due to the pressure drop created in the main lumen 1700 across the inletand outlet of the secondary lumen 1705. This has the benefit ofpreventing stagnant blood. As shown in FIG. 33B, by blocking flowthrough the main lumen 1700 of shunt 120, the flow can be divertedentirely to the secondary lumen 1705, thus increasing the flowresistance and reducing the blood flow rate. It will be appreciated thatadditional flow lumens could also be provided in parallel to allow for athree, four, or more discrete flow resistances. The shunt 120 may beequipped with a valve 1710 that controls flow to the main lumen 1700 andthe secondary lumen 1705 with the valve 1710 being controlled by thecontroller 1130 or being controlled manually by the user. The embodimentof FIGS. 33A and 33B has an advantage in that this embodiment in that itdoes not require as small of lumen sizes to achieve desired retrogradeflow rates as some of the other embodiments of variable flow resistancemechanisms. This is a benefit in blood flow lines in that there is lesschance of clogging and causing clots in larger lumen sizes than smallerlumen sizes.

The shunt 120 can also be arranged in a variety of coiled configurationswhich permit external compression to vary the flow resistance in avariety of ways. Arrangement of a portion of the shunt 120 in a coilcontains a long section of the shunt in a relatively small area. Thisallows compression of a long length of the shunt 120 over a small space.As shown in FIGS. 34A and 33B, a portion of the shunt 120 is woundaround a dowel 1805 to form a coiled region. The dowel 1805 has plates1810 a and 1810 b which can move toward and away from each other in anaxial direction. When plates 1810 a and 1810 b are moved away from eachother, the coiled portion of the shunt 105 is uncompressed and flowresistance is at a minimum. The shunt 120 is large diameter, so when theshunt is non-compressed, the flow resistance is low, allowing ahigh-flow state. To down-regulate the flow, the two plates 1810 a and1810 b are pushed together, compressing the coil of shunt 120. By movingthe plates 1810 a and 1810 b together, as shown in FIG. 34B, the coiledportion of the shunt 120 is compressed to increase the flow resistance.The controller 1130 can control the plates or they can be controlledmanually by the user.

A similar compression apparatus is shown in FIGS. 35A and 35B. In thisconfiguration, the coiled shunt 120 is encased between two movablecylinder halves 1905 a and 1905 b. The halves 1905 a and 1905 b canslide along dowel pins 1910 to move toward and away from one another.When the cylinder halves 1905 are moved apart, the coiled shunt 120 isuncompressed and flow resistance is at a minimum. When the cylinderhalves 1905 are brought together, the coiled shunt 120 is compressedcircumferentially to increase flow resistance. The controller 1130 cancontrol the halves 1905 or they can be controlled manually by the user.

As shown in FIGS. 36A through 36D, the shunt 120 may also be woundaround an axially split mandrel 2010 having wedge elements 2015 onopposed ends. By axially translating wedge elements 2015 in and out ofthe split mandrel 2010, the split portions of the mandrel are opened andclosed relative to one another, causing the coil of tubing to bestretched (when the mandrel portions 2010 are spread apart, FIG. 36C,36D) or relaxed (when the mandrel portions 2010 are closed, FIG. 36A,36B.) Thus, when the wedge elements 2015 are spaced apart, as shown inFIGS. 36A and 36B, the outward pressure on the shunt 120 is at a minimumand the flow resistance is also at a minimum. By driving the wedgeelements 2015 inwardly, as shown in FIGS. 36C and 36D, the split mandrelhalves 2020 are forced apart and the coil of shunt 120 is stretched.This has the dual effect of decreasing the cross sectional area of theshunt and lengthening the shunt in the coiled region, both of which leadto increased flow resistance.

FIGS. 37A and 37B show an embodiment of the variable resistancecomponent 1125 that uses a dowel to vary the resistance to flow. Ahousing 2030 is inserted into a section of the shunt 120. The housing2030 has an internal lumen 2035 that is contiguous with the internallumen of the shunt 120. A dowel 2040 can move into and out of a portionof the internal lumen 2035. As shown in FIG. 37A, when the dowel 2040 isinserted into the internal lumen 2035, the internal lumen 2035 isannular with a cross-sectional area that is much smaller than thecross-sectional area of the internal lumen 2035 when the dowel is notpresent. Thus, flow resistance increases when the dowel 2040 ispositioned in the internal lumen 2035. The annular internal lumen 2035has a length S that can be varied by varying the portion of the dowel2040 that is inserted into the lumen 2035. Thus, as more of the dowel2040 is inserted, the length S of the annular lumen 2035 increases andvice-versa. This can be used to vary the level of flow resistance causedby the presence of the dowel 2040.

The dowel 2040 enters the internal lumen 2035 via a hemostasis valve inthe housing 2030. A cap 2050 and an O-ring 2055 provide a sealingengagement that seals the housing 2030 and dowel 2040 against leakage.The cap 2050 may have a locking feature, such as threads, that can beused to lock the cap 2050 against the housing 2030 and to also fix theposition of the dowel 2040 in the housing 2040. When the cap 2050 islocked or tightened, the cap 2050 exerts pressure against the O-ring2055 to tighten it against the dowel 2040 in a sealed engagement. Whenthe cap 2050 is unlocked or untightened, the dowel 2040 is free to movein and out of the housing 2030.

Exemplary Intervention Procedure

Referring now to FIGS. 38A-38E, 39, 40A-40E, and 41A-41F, an exemplaryinterventional procedure is described. The procedure is described as acarotid artery stenting procedure although it should be appreciated thatthe devices described herein can be used with various types ofinterventional procedures. Initially, as shown in FIG. 38A, the suturedelivery device 5 with a pre-mounted distal sheath 605 is inserted intothe common carotid artery CCA over a pre-placed guidewire 31. (Thecommon carotid artery CCA is shown schematically in FIGS. 38A-38B and itshould be appreciated that the actual anatomical details may differ.)The suture delivery device 5 is positioned relative to the premountedsheath 605 such that a distal region of the suture delivery device'sshaft 7 protrudes out of the distal end of the sheath 605 to provideaccess to the blood vessel wall for the suture delivery device 5.

With reference to FIG. 38B, the suture delivery device 5 is then used todeploy closing suture 19 into the vessel wall as described above toachieve pre-placement of the closing suture prior to insertion of thesheath 605 into the vessel. At least one end of the suture 19 is drawnoutside the body of the patient using the suture delivery device suchthat the suture 19 can be held until such time as the suture is to betied off to create a permanent closure of the arteriotomy. With thesuture 19 placed, the distal sheath 605 is then advanced distally overthe shaft 7 of the suture delivery device 5 into the vessel such thatthe distal end of the sheath 605 is positioned in the vessel and aproximal end of the sheath 605 protrudes out of the patient, as shown inFIG. 38C. In this manner, the sheath 605 provides access to the insideof the vessel.

The suture delivery device 5 is then removed from the sheath 605. FIG.38D shows the sheath 605 positioned to provide access to the interior ofthe vessel with the suture delivery device removed. In an embodiment, adetachable proximal extension tube 610 may then be attached to theprocedural sheath, as shown in FIG. 38E.

Alternately, as shown in FIG. 39, the arterial access device 110, withthe proximal extension tube 610 pre-attached or permanently affixed tothe distal sheath 610, may be inserted into the common carotid arteryCCA without pre-placement of closing sutures, using either a directsurgical access or a percutaneous access. After the sheath 605 of thearterial access device 110 has been introduced into the common carotidartery CCA, the blood flow will continue in antegrade direction AG withflow from the common carotid artery entering both the internal carotidartery ICA and the external carotid artery ECA, as shown in FIG. 40A.

The venous return device 115 is then inserted into a venous return site,such as the internal jugular vein. The shunt 120 is used to connect theflow lines 615 and 915 of the arterial access device 110 and the venousreturn device 115, respectively. In this manner, the shunt 120 providesa passageway for retrograde flow from the arterial access device 110 tothe venous return device 115. This entire circuit is shown in FIG. 28.In another embodiment, the shunt 120 connects to an external receptacle130 rather than to the venous return device 115.

Once all components of the system are in place and connected, flowthrough the common carotid artery CCA is stopped, typically using theocclusion element 129 as shown in FIG. 40B. The occlusion element 129 isexpanded at a location proximal to the distal opening of the sheath 605to occlude the CCA. Alternately, a tourniquet or other external vesselocclusion device can be used to occlude the common carotid artery CCA tostop flow therethrough. In an alternative embodiment, the occlusionelement 129 is introduced on second occlusion device 112 separate fromthe distal sheath 605 of the arterial access device 110. The ECA mayalso be occluded with a separate occlusion element, either on the samedevice 110 or on a separate occlusion device.

At that point retrograde flow RG from the external carotid artery ECAand internal carotid artery ICA will begin and will flow through thesheath 605, the flow line 615, the shunt 120, and into the venous returndevice 115 via the flow line 915. The flow control assembly 125regulates the retrograde flow as described above. FIG. 40B shows theoccurrence of retrograde flow RG. While the retrograde flow ismaintained, a stent delivery catheter 2110 is introduced into the sheath605, as shown in FIG. 40C. The stent delivery catheter 2110 isintroduced into the sheath 605 through the hemostasis valve 615 and theproximal extension 610 (not shown in FIGS. 40A-40E) of the arterialaccess device 110. The stent delivery catheter 2110 is advanced into theinternal carotid artery ICA and a stent 2115 deployed at the bifurcationB, as shown in FIG. 40D.

The rate of retrograde flow can be increased during periods of higherrisk for emboli generation for example while the stent delivery catheter2110 is being introduced and optionally while the stent 2115 is beingdeployed. The rate of retrograde flow can be increased also duringplacement and expansion of balloons for dilatation prior to or afterstent deployment. An atherectomy can also be performed before stentingunder retrograde flow.

Still further optionally, after the stent 2115 has been expanded, thebifurcation B can be flushed by cycling the retrograde flow between alow flow rate and high flow rate. The region within the carotid arterieswhere the stent has been deployed or other procedure performed may beflushed with blood prior to reestablishing normal blood flow. Inparticular, while the common carotid artery remains occluded, a ballooncatheter or other occlusion element may be advanced into the internalcarotid artery and deployed to fully occlude that artery. The samemaneuver may also be used to perform a post-deployment stent dilatation,which is typically done currently in self-expanding stent procedures.Flow from the common carotid artery and into the external carotid arterymay then be reestablished by temporarily opening the occluding meanspresent in the artery. The resulting flow will thus be able to flush thecommon carotid artery which saw slow, turbulent, or stagnant flow duringcarotid artery occlusion into the external carotid artery. In addition,the same balloon may be positioned distally of the stent during reverseflow and forward flow then established by temporarily relievingocclusion of the common carotid artery and flushing. Thus, the flushingaction occurs in the stented area to help remove loose or looselyadhering embolic debris in that region.

Optionally, while flow from the common carotid artery continues and theinternal carotid artery remains blocked, measures can be taken tofurther loosen emboli from the treated region. For example, mechanicalelements may be used to clean or remove loose or loosely attached plaqueor other potentially embolic debris within the stent, thrombolytic orother fluid delivery catheters may be used to clean the area, or otherprocedures may be performed. For example, treatment of in-stentrestenosis using balloons, atherectomy, or more stents can be performedunder retrograde flow In another example, the occlusion balloon cathetermay include flow or aspiration lumens or channels which open proximal tothe balloon. Saline, thrombolytics, or other fluids may be infusedand/or blood and debris aspirated to or from the treated area withoutthe need for an additional device. While the emboli thus released willflow into the external carotid artery, the external carotid artery isgenerally less sensitive to emboli release than the internal carotidartery. By prophylactically removing potential emboli which remain, whenflow to the internal carotid artery is reestablished, the risk of embolirelease is even further reduced. The emboli can also be released underretrograde flow so that the emboli flows through the shunt 120 to thevenous system, a filter in the shunt 120, or the receptacle 130.

After the bifurcation has been cleared of emboli, the occlusion element129 or alternately the tourniquet 2105 can be released, reestablishingantegrade flow, as shown in FIG. 40E.

If closing sutures were not preplaced in the vessel at the beginning ofthe procedure, they may be placed at this time. If the proximalextension tube 610 was attached to the sheath 605 (as shown in FIG. 39),the proximal extension tube 610 is detached from the sheath 605, asshown in FIG. 41A. A suture-based vessel closure device such asdescribed herein is inserted through the hemostasis valve 621 on thedistal sheath 605 and into the vessel. As shown in FIG. 41C, the distalsheath 605 is then withdrawn proximally to expose the distal region ofthe suture-based vessel closure device to the vessel wall. This is shownin more detail in the enlarged view of FIG. 41D. The closing suture 19is then inserted into the vessel wall and the suture-based vesselclosure device as well as the sheath 605 are removed from the bloodvessel, as shown in FIG. 41E. The suture ends are tied off to achievehemostasis of the arterial access site, as shown in FIG. 41F.

Alternately, a guidewire is inserted into the arterial access device110, and the arterial access device 110 is removed, leaving theguidewire in place. A suture closure device such as described herein isadvanced over the guidewire into the artery, and the closing suture isinserted into the vessel wall. The device is removed and the suture endsare tied off to achieve hemostasis of the arterial access site.

In an embodiment, the user first determines whether any periods ofheightened risk of emboli generation may exist during the procedure. Asmentioned, some exemplary periods of heightened risk include (1) duringperiods when the plaque P is being crossed by a device; (2) during aninterventional procedure, such as during delivery of a stent or duringinflation or deflation of a balloon catheter or guidewire; (3) duringinjection or contrast. The foregoing are merely examples of periods ofheightened risk. During such periods, the user sets the retrograde flowat a high rate for a discreet period of time. At the end of the highrisk period, or if the patient exhibits any intolerance to the high flowrate, then the user reverts the flow state to baseline flow. If thesystem has a timer, the flow state automatically reverts to baselineflow after a set period of time. In this case, the user may re-set theflow state to high flow if the procedure is still in a period ofheightened embolic risk.

In another embodiment, if the patient exhibits an intolerance to thepresence of retrograde flow, then retrograde flow is established onlyduring placement of a filter in the ICA distal to the plaque P.Retrograde flow is then ceased while an interventional procedure isperformed on the plaque P. Retrograde flow is then re-established whilethe filter is removed. In another embodiment, a filter is places in theICA distal of the plaque P and retrograde flow is established while thefilter is in place. This embodiment combines the use of a distal filterwith retrograde flow.

Additional Embodiment

FIGS. 42A and 42B show another embodiment of a suture delivery device4205 that is configured to deliver a suture. The device 4205 isdescribed in the context of delivering a suture to an arterial accesssite prior to insertion of an introducer sheath. In the exemplaryembodiment of FIGS. 42A through 46, the device 4205 can be used in theregion of the common carotid artery CCA. As shown in FIG. 42A, thedevice 4205 includes a removable guidewire segment 4210 which can befixedly or removably affixed to the distal end of a body or distalhousing 4215 of the device 4205. The device 4205 includes a mechanism,such as any of the mechanisms described herein, for delivering a closuresuture to an opening in the CCA. The guidewire segment 4210 may be inthe form of an elongated portion of a guidewire. In an embodiment, theguidewire segment 4210 has a length of about 5 cm to 15 cm. In anembodiment, the guidewire segment 4210 has a length of about 8 to 12 cm.

The removable guidewire segment 4210 can be detached from the distalhousing 4215 and removably or fixedly attached to a proximal wireextension 4230 via a coupler 4235. The coupler 4235 may be integral tothe proximal end of the removable guidewire segment. Alternately, thecoupler 4235 may be integral to the distal end of the proximal wireextension 4230 and a corresponding coupler may be integral to the distalend of the suture delivery device 4205. The removable guidewire segment4210 and proximal wire extension 4230 are positioned end-to-end inseries (with the coupler 4235 connecting the two) such that theycollectively form an elongated guidewire, as shown in FIG. 42B. Aftersuture placement at the arterial access site, the guidewire can be usedto guide the insertion of an introducer sheath into the artery. Thecoupler 4235 is configured such that when the guidewire segment 4210 andproximal wire extension 4230 are coupled together, they act as a singleguidewire. The coupler 4235 creates minimal to no increase in diameterwith the guidewire, and also has smooth edges, such that there is nostep or substantially no step at the juncture of the coupler 4235 withthe guidewire segment 4210 or the proximal wire extension 4230. That is,there is a smooth transition between the guide wire portions and thecoupler. Thus, there is little or no risk while inserting devices suchas the introducer sheath over the guidewire that the device will snag onthe coupler 4235. The coupler outer diameter therefore does notinterfere with its function as an introducer sheath guidewire. Thecoupler 4235 may vary in structure. For example, the coupler 4235 may bea screw, snap, or other spring coupler which may be actuated to detachand attach the removable guidewire segment 4210 to the extension 4230.

An insertion tool may be configured to facilitate attaching theremovable guidewire segment 4210 to the proximal wire extension 4230,both of which are very small diameter components and may be difficult tosee and handle. For example, an insertion tool may have a guide channelwith wide lead-in funnels on both ends to insert the wire tip 4210 onone side, and the proximal wire extension 4230 on the other. The guidechannel directs the two sides to be properly positioned as they arepushed or twisted together, depending on the coupler mechanism. Thechannel can be designed so that the coupled guidewire can then be liftedout. In a further embodiment, the insertion tool may also include afeature such as a pin which may actuate a spring lock on the coupler4235 when the two sides 4210 and 4230 are properly positioned in theinsertion tool. The feature is actuated to lock or unlock the coupler4235 to couple or uncouple the two sides 4210 and 4230.

The aforementioned process is described in more detail with reference toFIGS. 43-46. Prior to inserting the device 4205 into the artery, a micropuncture catheter or a needle can be used to position the removable tip4210 (without the device 4205 attached) into the blood vessel. Once theremovable guidewire segment 4210 is positioned within the vessel, theproximal end of the tip 4210 (which is still outside the vessel and/orthe body) is attached to the distal housing 4215 of the device 4205. Asshown in FIG. 43, the device 4205 is then introduced into the artery.

With reference now to FIG. 44, the device 4205 can then be used todeploy a suture 4212 into the vessel wall according to any of themethods described above. As shown in FIG. 45, the suture delivery device4205 (with the removable tip 4215 attached) can then be removed from thevessel while tension is maintained on the sutures for hemostasis. Whilethe sutures 4212 are maintained in tension, the device 4205 is pulledback by a user such that the distal housing 4215 is exposed outside theskin. The removable guidewire segment 4210 can then be detached from thedevice 4205 so that the proximal end of the guidewire segment 4210 isfree and detached and outside the artery.

The proximal end of the guidewire segment 4210 is then attached to theproximal wire extension 4230 via the coupler 4235 as shown in FIG. 46.The detachable guidewire segment 4210 plus extension 4230 create anextended length for the guidewire suitable for deployment of a device,such as an introducer sheath, over the guidewire. That is, the guidewiresegment 4210 and proximal wire extension 4230 collectively form aguidewire having a region inside the artery and a region outside theartery.

In an additional step, as shown in FIG. 47, a device, such as anintroducer sheath 4250 with an inner dilator 4260, is inserted over theguidewire that is collectively formed by the guidewire segment 4210 andproximal wire extension 4230 and into the vessel.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope of the subject matterdescribed herein. Any recited method can be carried out in the order ofevents recited or in any other order which is logically possible.

Although embodiments of various methods and devices are described hereinin detail with reference to certain versions, it should be appreciatedthat other versions, embodiments, methods of use, and combinationsthereof are also possible. Therefore the spirit and scope of theappended claims should not be limited to the description of theembodiments contained herein.

The invention claimed is:
 1. A method comprising: delivering, via anassembly, a suture element to an aperture in a vessel wall, the assemblycomprising: a body comprising the suture element held within the bodyand at least one suture capture rod within the body, the suture capturerod being operatively associated with the suture element and arranged topass the suture element through the vessel wall such that opposedportions of the suture element extend from the vessel wall, the bodyfurther comprising a distal housing portion at a distal end of the body;a proximal guidewire extension; and a removable guidewire segment;wherein the assembly comprises a first configuration and a secondconfiguration; wherein in the first configuration the removableguidewire segment is removably attached to the distal housing portion ofthe body and detached from the proximal guidewire extension, and in thesecond configuration the removable guidewire segment is detached fromthe body and removably attached via a coupling component to a distal endof the proximal guidewire extension such that there is a first smoothtransition at a first juncture between the proximal guidewire extensionand the coupling component and a second smooth transition at a secondjuncture between the removable guidewire segment and the couplingcomponent; wherein the assembly is configured to pass the suture elementthrough the vessel wall in the first configuration.
 2. The method ofclaim 1, wherein the removable guidewire segment is configured to beattached in series to the proximal guidewire extension.
 3. The method ofclaim 2, wherein the proximal guidewire extension and the removableguidewire segment collectively form an elongated guidewire when attachedto one another.
 4. The method of claim 3, wherein an outer diameter ofthe coupling component does not interfere with a function of theelongated guidewire as an introducer sheath guidewire.
 5. The method ofclaim 4, wherein the coupling component does not form a step at thefirst and second junctures.
 6. The method of claim 4, wherein thecoupling component can be used to attach the proximal guidewireextension to the removable guidewire segment with the use of aninsertion tool.
 7. The method of claim 4, wherein the coupling componentcan be used to attach the proximal guidewire extension to the removableguidewire segment without the use of an external tool.
 8. The method ofclaim 2, wherein the coupling component is a screw, snap, or a springcoupler.